Without which two elements does NIST say a contingency test plan cannot show the plan is effective? Choose two.

Answer: D. Explicit test objectives
C. Explicit success criteria

SP 800-34r1 states the test plan should include explicit objectives and associated success criteria, without which the effectiveness of the plan and its elements cannot be determined.

Source: NIST SP 800-34 Rev. 1 (NIST) — Sec. 3.5.1 Testing