Employees must be continually made aware of the policy and expectations of their behavior. Choice A would have little relevant bearing on the employee's behavior. Choice B does not involve the employees. Choice C could be an aspect of continual reinforcement of the security policy.

Explanation
A challenge/response mechanism prevents replay attacks by sending a different random challenge in each authentication event. The response is linked to that challenge. Therefore, capturing the authentication handshake and replaying it through the network will not work. Using hashes by itself will not prevent a replay.
A WEP key will not prevent sniffing (it just takes a few more minutes to break the WEP key if the attacker does not already have it) and therefore will not be able to prevent recording and replaying an authentication handshake. HTTP Basic Authentication is clear text and has no mechanisms to prevent replay.

Section: INFORMATION RISK MANAGEMENT
Explanation:
The data owners should be notified first so they can take steps to determine the extent of the damage and coordinate a plan for corrective action with the computer incident response team. Other parties will be notified later as required by corporate policy and regulatory requirements.

Explanation
A Trojan is a program that gives the attacker full control over the infected computer, thus allowing the attacker to hijack, copy or alter information after authentication by the user. IP spoofing will not work because IP is not used as an authentication mechanism. Man-in-the-middle attacks are not possible if using SSL with client-side certificates. Repudiation is unlikely because client-side certificates authenticate the user.