Choose the correct article: ____ honesty is the best policy.

Answer: No article — the complete sentence is: Honesty is the best policy.

• Honesty is an abstract (uncountable) noun when used in a general sense, so it does not take an article here.

• Proverbs and general truths normally use the zero article before abstract nouns.

• Why the other choices are wrong: 'A' or 'An' require singular countable nouns; 'The' would make the noun specific, which does not fit a general proverb.

Note: 'the' can be correct when referring to a specific instance, e.g., The honesty you showed yesterday impressed everyone.