The correct answer is option 3, which states that national emergency has been declared in India three times since Independence. A national emergency is a state of emergency declared by the President of India when the security or integrity of the nation is threatened by war, external aggression, or internal disturbances. The article 352 of the Indian Constitution empowers the President to declare a national emergency.

The first national emergency was declared in 1962 during the Sino-Indian War. The second national emergency was declared in 1971 during the Indo-Pakistani War. The third national emergency was declared in 1975, known as the Emergency era, when Prime Minister Indira Gandhi suspended civil liberties and imposed strict political repression.

It is important to note that the correct answer may change in the future if any more national emergencies are declared.