Which one of the following countries shares border with the least number of states/UTs of India? 

Option a is incorrect: China shares border with Ladakh, Himachal Pradesh, Uttarakhand, Sikkim, and Arunachal Pradesh (5 states/UTs). Option b is incorrect: Nepal shares border with Uttarakhand, Uttar Pradesh, Bihar, West Bengal, and Sikkim (5 states/UTs) Option c is incorrect: Bangladesh shares border with West Bengal, Assam, Meghalaya, Tripura, and Mizoram (5 states/UTs). Option d is correct: Myanmar shares border with Arunachal Pradesh, Nagaland, Manipur, and Mizoram (4 states/UTs).