Answer:
D. Brute force attack
Explanation:
A Brute Force Attack is the fastest way of accessing a website or database (or whatsoever secured by a password). It attempts repeatedly different combinations of usernames and passwords till it breaks in.
This repeated behavior is just like an enemy that attacks a fort.
Optionally, using a key derivation function, the attacker can try to guess the key generally created from the password. This is known as an exhaustive key search.
