The answer is Bhutan.
A. Afghanistan is a landlocked country located in South Asia. It is bordered by Pakistan to the west, Iran to the southwest, Turkmenistan, Uzbekistan, and Tajikistan to the north, China to the northeast, and India to the east and southeast.
B. Bhutan is a landlocked country located in the Eastern Himalayas. It is bordered by China to the north and India to the south, east, and west.
C. India is a country in South Asia. It is the second-most populous country in the world, with over 1.3 billion people. It is the seventh-largest country by area, covering 3.287 million square kilometers (1.269 million square miles).
D. Pakistan is a country in South Asia. It is the fifth-most populous country in the world, with over 230 million people. It is the sixth-largest country by area, covering 880,940 square kilometers (340,509 square miles).
Bhutan is the only country in the list that is not a member of the South Asian Association for Regional Cooperation (SAARC). SAARC is an intergovernmental organization that promotes economic, social, and cultural development among its member states.