Explanation:

- The Line of Actual Control (LAC) is the demarcation that separates Indian-controlled territory from Chinese-controlled territory, serving as the de facto border between India and China.

- Option 4: China - The LAC is between India and China, highlighting ongoing disputes.

- Option 1: Bangladesh - Shares the longest international border with India, but not the LAC.

- Option 2: Myanmar - Shares a northeastern border with India, but not the LAC.

- Option 3: Afghanistan - Does not share a direct border with India, so the LAC is not relevant.