The knowledge engineer usually has a computer-related and expert system background, but does not have the knowledge of the specific discipline or domain being addressed by the expert system. For example, the expert system being developed may be a medical diagnostic system requiring input from diagnostic specialists and other types of physicians. These individuals are the domain experts. It is the job of the knowledge engineer to elicit the critical knowledge from the domain expert and incorporate it into the expert system knowledge base. The term object designer in the answers is a distracter.

This document provides recommendations for the implementation of public- key cryptography based on the RSA algorithm, covering the following aspects:
cryptographic primitives; encryption schemes; signature schemes with appendix; ASN.1 syntax for representing keys and for identifying the schemes.
Reference(s) used for this question:
RSA Laboratories at http://www.emc.com/emc-plus/rsa-labs/standards-initiatives/pkcs-rsa- cryptography-standard.htm

Explanation/Reference:
Explanation:
Object reuse requirements, applying to systems rated TCSEC C2 and above, are used to protect files, memory, and other objects in a trusted system from being accidentally accessed by users who are not authorized to access them.
Deleting files on disk before reusing the space does not meet this requirement and is therefore not appropriate in addressing object reuse.
Deleting files on disk merely erases file headers in a directory structure. It does not clear data from the disk surface, thus making files still recoverable. All other options involve clearing used space, preventing any unauthorized access.
Incorrect Answers:
A: Degaussing magnetic tapes when they're no longer needed protects files from unauthorized access by destroying the data on the tapes. This is a valid method of addressing object reuse.
C: Clearing memory blocks before they are allocated to a program or data removes any residual data from the memory thus preventing unauthorized access. This is a valid method of addressing object reuse.
D: Clearing buffered pages, documents, or screens from the local memory of a terminal or printer removes any residual data from the memory thus preventing unauthorized access. This is a valid method of addressing object reuse.