TACACS+ is a proprietary Cisco enhancement to TACACS and is more robust than RADIUS. PAP is not a remote access authentication system but a remote node security protocol.
Source: KRUTZ, Ronald L. & VINES, Russel D., The CISSP Prep Guide: Mastering the Ten Domains of Computer Security, John Wiley & Sons, 2001, Chapter 3: Telecommunications and Network Security (page 122).

Echo replies outbound should be dropped, not allowed. There is no reason for any internet users to send ICMP ECHO Request to your interal hosts from the internet. If they wish to find out if a service is available, they can use a browser to connect to your web server or simply send an email if they wish to test your mail service.
Echo replies outbound could be used as part of the SMURF amplification attack where someone will send ICMP echo requests to gateways broadcast addresses in order to amplify the request by X number of users sitting behind the gateway.
By allowing inbound echo requests and outbound echo replies, it makes it easier for attackers to learn about the internal network as well by performing a simply ping sweep. ICMP can also be used to find out which host has been up and running the longest which would indicates which patches are missing on the host if a critical patch required a reboot.
ICMP can also be use for DDoS attacks, so you should strictly limit what type of ICMP traffic would be allowed to flow through your firewall.
On top of all this, tools such as LOKI could be use as a client-server application to transfer files back and forward between the internat and some of your internal hosts. LOKI is a client/server program published in the online publication Phrack . This program is a working proof-of-concept to demonstrate that data can be transmitted somewhat secretly across a
network by hiding it in traffic that normally does not contain payloads. The example code
can tunnel the equivalent of a Unix RCMD/RSH session in either ICMP echo request (ping)
packets or UDP traffic to the DNS port. This is used as a back door into a Unix system after
root access has been compromised. Presence of LOKI on a system is evidence that the
system has been compromised in the past.
The outbound echo request and inbound echo reply allow internal users to verify
connectivity with external hosts.
The following answers are incorrect:
Allow echo request outbound The outbound echo request and inbound echo reply allow
internal users to verify connectivity with external hosts.
Drop echo request inbound There is no need for anyone on the internet to attempt pinging
your internal hosts.
Allow echo reply inbound The outbound echo request and inbound echo reply allow internal
users to verify connectivity with external hosts.
Reference(s) used for this question:
http://www.phrack.org/issues.html?issue=49&id=6
STREBE, Matthew and PERKINS, Charles, Firewalls 24seven, Sybex 2000, Chapter 10:
The Perfect Firewall.

Explanation/Reference:
This is another name for the demilitarized zone (DMZ) of a network.
"Three legged firewall" is incorrect. While a DMZ can be implemented on one leg of such a device, this is not the best answer.
"A place to attract hackers" is incorrect. The DMZ is a way to provide limited public access to an organization's internal resources (DNS, EMAIL, public web, etc) not as an attractant for hackers.
"Bastion host" is incorrect. A bastion host serves as a gateway between trusted and untrusted network.
References:
CBK, p. 434
AIO3, pp. 495 - 496

Section: Risk, Response and Recovery
Explanation/Reference:
Circumstantial evidence is defined as inference of information from other, intermediate, relevant facts.
Secondary evidence is a copy of evidence or oral description of its contents. Conclusive evidence is incontrovertible and overrides all other evidence and hearsay evidence is evidence that is not based on personal, first-hand knowledge of the witness, but was obtained from another source. Computer-generated records normally fall under the category of hearsay evidence.
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).

Explanation/Reference:
The underlying problem for a company with a lot of turnover is assuring that new employees are assigned the correct access permissions and that those permissions are removed when they leave the company.
Selecting the best answer requires one to think about the access control options in the context of a company with a lot of flux in the employee population. RBAC simplifies the task of assigning permissions because the permissions are assigned to roles which do not change based on who belongs to them. As employees join the company, it is simply a matter of assigning them to the appropriate roles and their permissions derive from their assigned role. They will implicitely inherit the permissions of the role or roles they have been assigned to. When they leave the company or change jobs, their role assignment is revoked/changed appropriately.
Mandatory access control is incorrect. While controlling access based on the clearence level of employees and the sensitivity of obects is a better choice than some of the other incorrect answers, it is not the best choice when RBAC is an option and you are looking for the best solution for a high number of employees constantly leaving or joining the company.
Lattice-based access control is incorrect. The lattice is really a mathematical concept that is used in formally modeling information flow (Bell-Lapadula, Biba, etc). In the context of the question, an abstract model of information flow is not an appropriate choice. CBK, pp. 324-325.
Discretionary access control is incorrect. When an employee joins or leaves the company, the object owner must grant or revoke access for that employee on all the objects they own. Problems would also arise when the owner of an object leaves the company. The complexity of assuring that the permissions are added and removed correctly makes this the least desirable solution in this situation.
References
Alll in One, third edition page 165
RBAC is discussed on pp. 189 through 191 of the ISC(2) guide.