The correct answer is B. CRIME Attack.

The scenario describes a compression-based side-channel attack against encrypted HTTPS traffic. The attacker observes differences in compressed response sizes and uses those differences to infer protected authentication values, such as cookies or session tokens.

CRIME, or Compression Ratio Info-leak Made Easy, abuses TLS/SPDY-level compression behavior. When attacker-controlled input is compressed together with secret values, response-size differences can reveal information about the secret. The CEH cryptography/session-hijacking context discusses attacks against SSL/TLS and secure communications, including man-in-the-middle positioning and cryptographic weaknesses affecting encrypted channels .

Option A. Forbidden Attack is incorrect because it is not the recognized compression side-channel attack described.

Option C. Man-in-the-Browser (MITB) Attack is incorrect because MITB requires malware inside the browser to intercept or modify browser transactions.

Option D. Man-in-the-Middle (MITM) Attack describes the attacker’s position, but not the specific compression-based technique.

Option B. CRIME Attack is correct because the attack extracts secrets by analyzing compressed encrypted response sizes.

Therefore, the best answer is B. CRIME Attack.