Antonym of ASSERT

Answer: Option B

Assert : state a fact or belief confidently and forcefully.
Agree : have the same opinion about something; concur.
Acquiesce : accept something reluctantly but without protest.
Abjure : solemnly renounce (a belief, cause, or claim).
Abdicate : (of a monarch) renounce one's throne.

Antonym of Assert is Acquiesce