Select the most appropriate antonym of the given word.

DUPLICITY

The correct antonym is Sincerity.

Explanation:
1. Duplicity means deceitfulness, double-dealing, or dishonesty in behavior or speech.
2. Sincerity means the quality of being free from pretense, deceit, or hypocrisy; honesty and truthfulness.
Since "sincerity" represents genuine behavior and honesty, it is the exact opposite (antonym) of "duplicity".

Meaning of the other options:
- Treachery: Violation of faith or betrayal of trust (synonym of duplicity).
- Deceit: The action or practice of deceiving someone (synonym of duplicity).
- Hypocrisy: The practice of claiming to have moral standards or beliefs to which one's own behavior does not conform (synonym of duplicity).