Step 1: 'Candid' derives from the Latin 'candidus', meaning white or pure, which extended in meaning to describe speech that is open, truthful, and without concealment.
Step 2: Check each option against this sense of openness. 'Secretive' means hiding information, the opposite of openness. 'Cautious' means careful or guarded in speech, again closer to withholding than revealing. 'Complicated' is unrelated to honesty or openness at all.
Step 3: 'Frank and honest' matches the core idea of candid: speaking openly and truthfully without holding back.
Correct option: (1) Frank and honest.