Which of the following countries is not included in South Asia?

The correct answer is China.

To understand why China is not included in South Asia, we can look at the definition and membership of the region:
South Asia is a well-defined geographical and geopolitical region in the southern part of the Asian continent. It is primarily defined by the member nations of the South Asian Association for Regional Cooperation (SAARC) and the prominent geographical boundary of the Himalayas.
The core countries that make up South Asia are:
1. India
2. Pakistan
3. Bangladesh
4. Nepal
5. Bhutan
6. Sri Lanka
7. Maldives
8. Afghanistan

Geographically and geopolitically, China is located to the north of the Himalayas and is classified as part of East Asia rather than South Asia. Therefore, while Pakistan, Bangladesh, and Nepal are all South Asian nations, China is not.