Explanation:

The 8th Schedule of the Constitution of India lists the official languages of the country. These languages are recognized and given official status at the national level. However, some of these languages are also the official languages of certain states within India.

Official Language of a State:
- The official language of a state is the language that is used for all official purposes within the state, such as in government offices, courts, and legislative assemblies. It is the language in which official documents and records are maintained.

Identification of the Official Language:
Among the languages listed in the 8th Schedule of the Constitution, Urdu is the official language of the state.

Explanation of Options:
- Kashmiri: Kashmiri is a language spoken in the Kashmir Valley of Jammu and Kashmir. While it is one of the languages listed in the 8th Schedule, it is not the official language of the state. The official language of Jammu and Kashmir is Urdu.
- Urdu: Urdu is the official language of the state. It is widely spoken and understood in many parts of the country, especially in North India. It is also the official language of Jammu and Kashmir.
- Sindhi: Sindhi is a language spoken in the Sindh region of Pakistan and parts of India. It is one of the languages listed in the 8th Schedule, but it is not the official language of any state in India.
- Nepali: Nepali is the official language of Nepal, and it is also one of the languages listed in the 8th Schedule. However, it is not the official language of any state in India.

Conclusion:
Among the languages listed in the 8th Schedule of the Constitution, Urdu is the official language of a state in India. It is the official language of Jammu and Kashmir. The state recognizes Urdu as the language for all official purposes within its jurisdiction.