Correct Answer: Renounce

Solution : The correct choice is the fourth option.

The appropriate antonym of renounce is endorse because it means to support or approve, while "renounce" means to formally reject or disapprove, providing a clear contrast in terms of approval or endorsement.

The meanings of the other options are as follows:

• Affirm means to confirm or state positively, which is somewhat similar to endorsing.
• Support means to aid or assist, often aligning with endorsement.
• Advocate means to publicly support or recommend.

Therefore, the correct answer is renounce.