Explanation:

The original sentence is erroneous.

Reason: Usage of the phrasal verb 'hold over' which means ‘to do something or deal with something at a later time or date' is inappropriate in this sentence.

'Hold back' which means ‘hesitate to act or speak; keep secret’ would be suitable in this context.

E.g.: I held back during the meeting because I knew that my opinions were too controversial.

Hence ‘held back’ should be used in place of ‘held over’ to make the sentence grammatically and contextually correct.

Among the given choices, only option B replaces the given bold part most appropriately.

The sentence after replacement becomes:

It is commendable that wing commander Abhinandan Varthaman held back crucial information even under situations of extreme stress.

Option B is hence the correct answer.