Still, in questions which have one correct answer (e.g. “Which is bigger, the earth or the sun” or “STALE is to STEAL as 89475 is to...”), I only mark the correct answer and “I don’t know” (if it’s there) as acceptable, and I mark the question as “Mandatory” if the “I don’t know” answer is available. It’s OK to be ignorant, but it’s not OK to not admit it.
Still, in questions which have one correct answer (e.g. “Which is bigger, the earth or the sun” or “STALE is to STEAL as 89475 is to...”), I only mark the correct answer and “I don’t know” (if it’s there) as acceptable, and I mark the question as “Mandatory” if the “I don’t know” answer is available. It’s OK to be ignorant, but it’s not OK to not admit it.