Explanation:

- Obligation: A duty or commitment that compels someone to do something. It implies a binding promise or sense of responsibility.

- Option 1: Choice: Refers to the ability to select freely between alternatives without any constraints. It implies freedom, which contrasts with obligation.

-Correct Answer: Choice as it represents the nearest antonym of obligation.

- Option 2: Compulsion: Denotes a forceful urge or pressure to act in a certain way. It is similar to obligation in that it implies a lack of freedom.

- Option 3: Silence: The absence of sound or communication. It is unrelated to obligation.

- Option 4: Covenant: An agreement or promise. It is more related to obligation as both involve commitments.