Mistake of law generally does not excuse performance, except as to misrepresentation of law or when a contract explicitly makes law relevant; most relief is for mistake of fact.

• A. It always excuses performance.
• B. It may excuse if there is misrepresentation of law or explicit law relevance; most relief is for mistake of fact.
• C. It requires rescission in all cases.
• D. It is the primary basis for contract rescission.

Answer: (A)