Comprehensive Detailed Explanation:To match the mitigation criteria, we analyze each machine’s CVSS (Common Vulnerability Scoring System) attributes:

Attack Vector (AV): N for network (matches the requirement of network-based attack).

Attack Complexity (AC): L for low (meets the requirement for low complexity).

Privileges Required (PR): N for none (indicating no privileges are needed).

User Interaction (UI): N for none (matches the requirement that no user action is needed).

Confidentiality (C), Integrity (I), and Availability (A): Requires high confidentiality and availability with low integrity.

From these criteria:

Computer1 requires user interaction (UI:R), which disqualifies it.

Computer2 has a local attack vector (AV:L), which disqualifies it for a network-based attack.

Computer3 has a high attack complexity (AC:H), which does not meet the low complexity requirement.

Computer4 meets all criteria: network attack vector, low complexity, no privileges, no user interaction, and appropriate confidentiality, integrity, and availability levels.

Thus, Computer4 is the correct answer.