Which statement is incorrect regarding the restoration of India-China relations?
1) Full diplomatic relations were restored in 1976.
2) Atal Behari Vajpayee visited China in 1979 as the External Affairs Minister.
3) Rajiv Gandhi was the first Indian Prime Minister to visit China after Nehru.
4) The emphasis on cultural exchange and Defense supplies increased significantly after the resumption of relations.

Choose the correct answer from the given options:

4 only

The process of normalizing relations between India and China spanned over a decade. The year 1976 marked the restoration of full diplomatic ties between these two nations. Notably, Atal Behari Vajpayee, who held the position of External Affairs Minister at that time, undertook a significant visit to China in 1979. Subsequently, Rajiv Gandhi became the first Prime Minister after Nehru to visit China. From that point onward, the focus has predominantly shifted towards fostering trade relations between India and China.