Which one of the following groups of Indian states shares a common international border with the Kingdom of Bhutan?

Introduction / Context:
India shares land borders with several neighbouring countries, and remembering which Indian states border each neighbour is an important part of political and regional geography. This question asks about the set of Indian states that have a common frontier with Bhutan, a small Himalayan kingdom located to the north of parts of eastern India.

Given Data / Assumptions:
• The country in question is Bhutan. • Options list different combinations of Indian states including Assam, Bihar, Meghalaya, Sikkim, West Bengal and Arunachal Pradesh. • We assume modern political boundaries and not older historical arrangements. • The aim is to identify the complete and correct group of Indian states that share a border with Bhutan.

Concept / Approach:
A quick mental map of north eastern India shows Bhutan located between Tibet region to the north and Indian states to the south. From west to east along the border with Bhutan we find the Indian states of Sikkim, West Bengal, Assam and Arunachal Pradesh. Bihar and Meghalaya lie further south and do not directly touch Bhutan. Therefore, we must pick the option that lists these four correct bordering states together.

Step-by-Step Solution:
Step 1: Identify Sikkim on the map, squeezed between Nepal and Bhutan, sharing a short border with Bhutan on its eastern side. Step 2: Move eastwards and notice that northern parts of West Bengal, especially the districts around Jalpaiguri and Alipurduar, touch Bhutan. Step 3: Further east, the state of Assam has a boundary with Bhutan along its northern districts. Step 4: To the east and north east of Bhutan lies Arunachal Pradesh, which also shares a border with Bhutan as well as with China and Myanmar. Step 5: Check the options and select the one that combines Arunachal Pradesh, Assam, Sikkim and West Bengal, which is option C.

Verification / Alternative check:
Cross checking with a political map of India confirms that Bihar and Meghalaya do not reach the Bhutan border. Bihar is located to the south of Nepal, and Meghalaya lies south of Assam. Therefore any option containing Bihar or Meghalaya alongside Bhutan is incorrect, while the combination of Arunachal Pradesh, Assam, Sikkim and West Bengal correctly matches the geographical reality.

Why Other Options Are Wrong:
Option A: Includes Bihar instead of Arunachal Pradesh, but Bihar does not border Bhutan. Option B: Includes Bihar and Meghalaya and omits Assam and Arunachal Pradesh, which makes it geographically incorrect. Option D: Excludes Arunachal Pradesh and adds Bihar, which again does not share a frontier with Bhutan.

Common Pitfalls:
Students sometimes confuse Nepal and Bhutan on the map and assume Bihar touches Bhutan because it borders Nepal. Another common error is to overlook the north eastern extensions of states like Assam and Arunachal Pradesh. To avoid these mistakes, practice tracing borders on a detailed political map and learn the border states for each neighbour country systematically.

Final Answer:
The Indian states that share a common frontier with Bhutan are Arunachal Pradesh, Assam, Sikkim and West Bengal.