The sentence describes a past action, so the past tense form of the verb "give" is required.
The past tense form of "give" is "gave".
The sentence becomes:
She gave an ambiguous answer.
The correct answer is "gave".
Arun’s present age in years is 40% of Barun’s. In another few years, Arun’s age will be half of Barun’s. By what percentage will Barun’s age increase during this period?