Explanation:

- Section 2: This section provides definitions for various terms used throughout the Indian Contract Act, such as "proposal," "acceptance," and "contract," but does not specifically address the revocation of proposals.

- Section 6: This section explains the methods by which a proposal can be revoked. It includes provisions like the communication of revocation, the lapse of time, failure of a condition, and death or insanity of the proposer.

- Section 3: This section deals with the communication, acceptance, and revocation of proposals, laying the groundwork for Sections 4 to 6, but without specifics on how revocation is made.

- Section 4: This details when communication of a proposal, acceptance, or revocation is complete, clarifying timing rather than methods.

Correct Answer: Option 2 - Section 6