The correct answer is C.
OBJ-2.4: A dictionary attack is a technique for defeating a cipher or authentication mechanism by trying to determine its decryption key or passphrase by trying hundreds or sometimes millions of likely possibilities, such as words in a dictionary. The key to answering this question is that they were using passwords from a list. In cryptography, a brute-force attack consists of an attacker submitting many passwords or passphrases with the hope of eventually guessing correctly. A dictionary attack is a specific form of a brute-force attack that uses a list. A session hijacking attack compromises the session token by stealing or predicting a valid session token to gain unauthorized access to the webserver. A man-in-the-middle attack (MITM), also known as a hijack attack, is an attack where the attacker secretly relays and possibly alters the communications between two parties who believe that they are directly communicating with each other.