A "Degausser (Otherwise known as a Bulk Eraser) has the main function of reducing to near zero the magnetic flux stored in the magnetized medium. Flux density is measured in Gauss or Tesla. The operation is speedier than overwriting and done in one short operation. This is achieved by subjecting the subject in bulk to a series of fields of alternating polarity and gradually decreasing strength.
The following answers are incorrect:Parity Bit Manipulation. Parity has to do with disk lerror detection, not data removal. A bit or series of bits appended to a character or block of characters to ensure that the information received is the same as the infromation that was sent.
Zeroization. Zeroization involves overwrting data to sanitize it. It is time-consuming and not foolproof. The potential of restoration of data does exist with this method. Buffer overflow. This is a detractor. Although many Operating Systems use a disk buffer to temporarily hold data read from disk, its primary purpose has no connection to data removal. An overflow goes outside the constraints defined for the buffer and is a method used by an attacker to attempt access to a system.
The following reference(s) were/was used to create this question:
Shon Harris AIO v3. pg 908 Reference: What is degaussing.

The order of classification from highest to lowest is: Sensitive, Confidential, Private, and Public. Review NIST Special Publication 800-26 for more details about information classifications.

Explanation/Reference:
Because computer-generated records normally fall under the category of hearsay evidence because they cannot be proven accurate and reliable this can be a problem.
Under the U.S. Federal Rules of Evidence, hearsay evidence is generally not admissible in court. This inadmissibility is known as the hearsay rule, although there are some exceptions for how, when, by whom and in what circumstances data was collected.
Source: KRUTZ, Ronald L. & VINES, Russel D., The CISSP Prep Guide: Mastering the Ten Domains of Computer Security, John Wiley & Sons, 2001, Chapter 9: Law, Investigation, and Ethics (page 310).
IMPORTANT NOTE:
For the purpose of the exam it is very important to remember the Business Record exemption to the Hearsay Rule. For example: if you create log files and review them on a regular basis as part of a business process, such files would be admissable in court and they would not be considered hearsay because they were made in the course of regular business and it is part of regular course of business to create such record.
Here is another quote from the HISM book:
Business Record Exemption to the Hearsay Rule
Federal Rules of Evidence 803(6) allow a court to admit a report or other business document made at or near the time by or from information transmitted by a person with knowledge, if kept in the course of regularly conducted business activity, and if it was the regular practice of that business activity to make the
[report or document], all as shown by testimony of the custodian or other qualified witness, unless the source of information or the method or circumstances of preparation indicate lack of trustworthiness.
To meet Rule 803(6) the witness must:
* Have custody of the records in question on a regular basis.
* Rely on those records in the regular course of business.
* Know that they were prepared in the regular course of business.
Audit trails meet the criteria if they are produced in the normal course of business. The process to produce the output will have to be proven to be reliable. If computer-generated evidence is used and admissible, the court may order disclosure of the details of the computer, logs, and maintenance records in respect to the system generating the printout, and then the defense may use that material to attack the reliability of the evidence. If the audit trails are not used or reviewed - at least the exceptions (e.g., failed log-on attempts) - in the regular course of business, they do not meet the criteria for admissibility.
Federal Rules of Evidence 1001(3) provide another exception to the hearsay rule. This rule allows a memory or disk dump to be admitted as evidence, even though it is not done in the regular course of business. This dump merely acts as statement of fact. System dumps (in binary or hexadecimal) are not hearsay because they are not being offered to prove the truth of the contents, but only the state of the computer.
BUSINESS RECORDS LAW EXAMPLE:
The business records law was enacted in 1931 (PA No. 56). For a document to be admissible under the statute, the proponent must show: (1) the document was made in the regular course of business; (2) it was the regular course of business to make the record; and (3) the record was made when the act, transaction, or event occurred, or shortly thereafter (State v. Vennard, 159 Conn. 385, 397 (1970); Mucci v. LeMonte,
157 Conn. 566, 570 (1969). The failure to establish any one of these essential elements renders the document inadmissible under the statute (McCahill v. Town and Country Associates, Ltd. , 185 Conn. 37 (1981); State v. Peary, 176 Conn. 170 (1978); Welles v. Fish Transport Co. , , 123 Conn. 49 (1937).
The statute expressly provides that the person who made the business entry does not have to be unavailable as a witness and the proponent does not have to call as a witness the person who made the record or show the person to be unavailable (State v. Jeustiniano, 172 Conn. 275 (1977).
The person offering the business records as evidence does not have to independently prove the trustworthiness of the record. But, there is no presumption that the record is accurate; the record's accuracy and weight are issues for the trier of fact (State v. Waterman, 7 Conn. App. 326 (1986); Handbook of Connecticut Evidence, Second Edition, § 11. 14. 3).
Reference: http://search.cga.state.ct.us/dtsearch_lpa.asp?cmd=getdoc&DocId=16833&Index=I%3A%
5Czindex%5C1995&HitCount=0&hits=&hc=0&req=&Item=712

Residual risk is "The security risk that remains after controls have been implemented" ISO/IEC TR 13335-1 Guidelines for the Management of IT Security (GMITS), Part 1: Concepts and Models for IT Security, 1996. "Weakness of an assets which can be exploited by a threat" is vulnerability. "The result of unwanted incident" is impact. Risk that remains after risk analysis has been performed is a distracter.
Risk can never be eliminated nor avoided, but it can be mitigated, transferred or accpeted. Even after applying a countermeasure like for example putiing up an Antivirus. But still it is not 100% that systems will be protected by antivirus.