The correct answer is option 2 - Bangladesh. Bangladesh shares the longest land border with India, stretching for about 4,096 kilometers. It is important to note that while China also shares a border with India, it is not the longest. The border between India and China measures approximately 3,488 kilometers. Nepal, another neighboring country of India, shares a shorter border of about 1,751 kilometers. Pakistan, which is often in the news due to its relationship with India, shares a border of around 3,323 kilometers. It is necessary to understand the geography of the region to answer this question correctly.