Which one of the following Indian states is almost surrounded by Bangladesh on three sides?

Introduction / Context:
India shares a long international boundary with Bangladesh, and several north eastern states are located close to or along this border. For map based and political geography questions, it is important to know which Indian states have extensive land borders with neighbouring countries. This question focuses on the state that is almost encircled by Bangladesh on three sides, leaving only a narrow connection to the rest of India.

Given Data / Assumptions:

• We are given four north eastern or eastern states: Nagaland, Assam, Arunachal Pradesh, and Tripura.
• We must find the state bordered by Bangladesh on three sides.
• We assume the current political boundaries of India and Bangladesh.
• The concept of three sided surrounding implies a near enclave like situation.

Concept / Approach:
Tripura is a small state in north east India that projects into Bangladeshi territory. Its western, northern, and southern boundaries are almost entirely shared with Bangladesh, while only a small eastern border connects it to Assam and Mizoram. By contrast, Nagaland, Assam, and Arunachal Pradesh share boundaries with other neighbours such as Myanmar, Bhutan, and China, and only limited stretches touch Bangladesh if at all. Recognising the peculiar shape and position of Tripura on the map is key.

Step-by-Step Solution:
Step 1: Recall the overall layout of the north eastern region of India, sometimes referred to as the seven sister states. Step 2: Note that Tripura is located to the south of Assam and is almost surrounded by Bangladesh on three sides. Step 3: Nagaland lies to the east and shares an international border mainly with Myanmar, not with Bangladesh. Step 4: Arunachal Pradesh lies to the north and shares borders primarily with China, Bhutan, and Myanmar. Step 5: Assam does share some boundary with Bangladesh, especially in its southern part, but it is not surrounded on three sides. Step 6: Therefore, Tripura matches the description of being nearly enclosed by Bangladesh.

Verification / Alternative check:
A map check confirms that Tripura has a very narrow link to the Indian mainland in the northeast and that its remaining sides touch Bangladesh. Additionally, standard exam maps often highlight Tripura as a state with a long border with Bangladesh relative to its size. This spatial pattern does not apply to the other states listed, which have more varied international borders, thereby confirming Tripura as the correct answer.

Why Other Options Are Wrong:
Nagaland borders Myanmar and some Indian states, but no part of it touches Bangladesh. Assam borders several Indian states and has a relatively short border with Bangladesh compared to its total perimeter, and not on three sides. Arunachal Pradesh borders China, Bhutan, and Myanmar but has no boundary with Bangladesh. As a result, they clearly do not satisfy the condition of being surrounded on three sides by Bangladesh.

Common Pitfalls:
Some learners mix up Assam and Tripura because both are in the north east and are mentioned frequently in border discussions. Others may not visualise the narrow neck of land that connects Tripura to the rest of India. To avoid these errors, practise reading outline maps of India and tracing each state's international borders. Remember that Tripura is the compact state that projects into Bangladesh and is almost enveloped by it.

Final Answer:
The Indian state that is surrounded by Bangladesh on three sides is Tripura.