 Layered Security Approach:

Secondary authentication adds another layer of security, contributing to the Defense in Depth strategy.

Enumerating costs ensures the layered approach is cost-effective and aligns with organizational budgets.

 Why This is Correct:

Secondary authentication strengthens access controls, a critical aspect of Defense in Depth.

 Why Other Options Are Incorrect:

A. Nonlinearities in metrics: Irrelevant to authentication processes.

C. System hardening: Focuses on system configurations, not authentication.

D. Anti-virus for mobile devices: Unrelated to authentication processes.

 References:

EC-Council highlights Defense in Depth strategies as essential for layered protection mechanisms like secondary authentication.