Correct Answer: decline

Solution : The correct choice is the first option.

Explanation:
Acknowledge: to admit the existence or truth of something.
Deny (antonym): to refuse to accept or acknowledge; to declare untrue.

The meanings of the other options are as follows:

• Accept: to agree to receive or undertake something.
• Own: to admit or acknowledge as true, to possess or acknowledge one's responsibility.
• Grant: to agree to give or allow.

Therefore, the correct answer is decline.