The McMahon Line, drawn in 1914, demarcated the border between:

India and China (Tibet)
India and Bhutan
India and Burma (Myanmar)
Assam and Arunachal Pradesh

The McMahon Line is a 2,400-kilometre (1,500 mi) border between India and China (Tibet). It was drawn in 1914 by the British government and the Tibetan government, but China has never accepted it. The McMahon Line runs from the tripoint with Burma (Myanmar) in the east to the tripoint with Nepal in the west. It demarcates the Indian state of Arunachal Pradesh from Tibet.

The McMahon Line was drawn in the Simla Convention of 1914, which was signed by the British government, the Tibetan government, and the Chinese government. The convention was intended to settle the border between India and Tibet. However, China never ratified the convention, and it has never accepted the McMahon Line as the border between China and India.

The McMahon Line has been a source of tension between India and China for many years. In 1962, China invaded India and captured territory along the McMahon Line. The two countries fought a brief war, and the McMahon Line was restored as the border between India and China. However, the border dispute remains a source of tension between the two countries.

The McMahon Line is a disputed border between India and China. It was drawn in 1914 by the British government and the Tibetan government, but China has never accepted it. The McMahon Line runs from the tripoint with Burma (Myanmar) in the east to the tripoint with Nepal in the west. It demarcates the Indian state of Arunachal Pradesh from Tibet.

The McMahon Line has been a source of tension between India and China for many years. In 1962, China invaded India and captured territory along the McMahon Line. The two countries fought a brief war, and the McMahon Line was restored as the border between India and China. However, the border dispute remains a source of tension between the two countries.

Option a is correct. The McMahon Line demarcated the border between India and China (Tibet).