You are trying to break into a highly secure mainframe system at a bank.

Comprehensive and Detailed Explanation:

This is a classic example of social engineering. When a system is well-secured technically, attackers often turn to exploiting human vulnerabilities — such as:

Talking to employees and gaining their trust

Bribing disgruntled or low-level staff

Gaining physical access or insider information through manipulation

From CEH v13 Courseware:

Module 7: Social Engineering

Incorrect Options:

A: Zero-days are rare and expensive; not always feasible.

C: DDoS is disruptive, not data-oriented.

D: MiTM is a complex network-based attack, unlikely effective against a hardened internal mainframe.