India shares its longest international land boundary with which neighbouring country?

Introduction / Context:
India shares land borders with several neighbouring countries in South Asia. For competitive exams and general awareness, it is important to know not only which countries border India, but also the relative lengths of these boundaries. This question asks you to identify the country with which India shares its longest international land boundary, which is an important fact in political and physical geography of the region.

Given Data / Assumptions:

• India shares borders with Bangladesh, China, Nepal, Bhutan, Pakistan, Myanmar, and others.
• The options provided are Bangladesh, China, Nepal, and Bhutan.
• We must select the country with which the length of the land boundary is the greatest.
• Approximate boundary lengths from standard geography references are assumed.

Concept / Approach:
To answer, we recall approximate border lengths. India Bangladesh boundary is a long and irregular one, crossing plains and riverine areas, and is often cited as being more than 4000 kilometres in length. India China border extends across the Himalayas and is shorter than the India Bangladesh boundary. The borders with Nepal and Bhutan are even shorter. By comparing these approximate figures, we can identify Bangladesh as having the longest land boundary with India.

Step-by-Step Solution:
Step 1: Recall that India shares a long and complex boundary with Bangladesh running through West Bengal, Assam, Meghalaya, Tripura, and Mizoram. Step 2: Remember that the India Bangladesh boundary length is commonly quoted as around 4096 kilometres, making it very long. Step 3: Note that the India China boundary, though extensive along the Himalayas, is shorter than the India Bangladesh boundary and is often quoted at around 3488 kilometres. Step 4: Recognise that the borders with Nepal and Bhutan are significantly shorter than those with Bangladesh and China. Step 5: Conclude that Bangladesh has the longest international land boundary with India.

Verification / Alternative Check:
An alternative check is to visualise the map of eastern India. The boundary with Bangladesh surrounds large parts of West Bengal and the northeastern states, including many enclaves and river segments. This makes the border very long and irregular. By contrast, the India China border is limited to mountainous areas and is more linear along the Himalayan crest. Basic data from standard geography textbooks confirm that the India Bangladesh boundary is the longest. This matches our reasoning and verifies the answer.

Why Other Options Are Wrong:
China is wrong because, although India shares a long border with China across Ladakh, Uttarakhand, Himachal Pradesh, Sikkim, and Arunachal Pradesh, its length is still less than the India Bangladesh boundary. Nepal is wrong because the India Nepal border, while important and open for people movement, is shorter and lies mainly along Uttar Pradesh and Bihar. Bhutan is wrong because it is a small Himalayan kingdom with a relatively short border length compared to Bangladesh or China.

Common Pitfalls:
Many learners guess China because it appears large on world maps and has geopolitical importance. Others may think of Pakistan, which is not listed in the options, due to frequent news coverage. The key is to rely on accurate geographical information rather than perception of political importance or country size. Remember also that irregular boundaries with many twists and turns, such as that with Bangladesh, can be longer than more linear mountainous borders.

Final Answer:
India shares its longest international land boundary with Bangladesh.