With which one of the following countries, India shares maximum length of the-border?

India shares its longest international land border with Bangladesh, covering a distance of approximately 4,096.7 km [1][t1]. This border is almost entirely encircled by Indian territory and was largely defined by the Radcliffe Award during the partition of India [c4][c5]. Following Bangladesh, the next longest borders are with China (3,488 km), Pakistan (3,323 km), and Nepal (1,751 km) [t1][t6]. The border with China is the second longest, accounting for about 26% of India's total land border [c3]. Nepal shares a 1,751 km border with five Indian states: Uttarakhand, Uttar Pradesh, Bihar, West Bengal, and Sikkim [c2]. In contrast, the shortest land border is with Afghanistan, measuring only 106 km [t1]. Therefore, Bangladesh is the correct answer as it significantly exceeds the border lengths of Pakistan, China, and Nepal.

Sources

1. [1] Geography of India ,Majid Husain, (McGrawHill 9th ed.) > Chapter 16: India–Political Aspects > INTERNATIONAL BOUNDARIES OF INDIA > p. 28