Explanation:

Myanmar shares its international border with four Indian states: Arunachal Pradesh, Nagaland, Manipur, and Mizoram. Sikkim, located in the Eastern Himalayas, shares borders with Nepal, Bhutan, and China, but not with Myanmar. Therefore, option C is correct. Option A, Arunachal Pradesh, Option B, Mizoram, and Option D, Manipur, all share significant portions of their eastern borders with Myanmar. Thus, A, B, and D are incorrect as they do share a boundary with Myanmar.