This question checks a shared date in the modern history of India and Bangladesh, tied to the end of the 1971 war. Let's look at each date given.
The surrender ceremony and the birth of Bangladesh both happened on 16 December 1971, which is why this date is jointly observed as Victory Day in Bangladesh and Vijay Diwas in India.
Let's summarize:
So the correct answer is option (b), 16 December.