The correct answer is: A. Persian
Persian was the official language of the Sultanate of Delhi. It was used in government, administration, and education. It was also the language of literature and poetry.
Urdu is a language that developed in the 12th century in the Indian subcontinent. It is a mix of Persian, Arabic, and Hindi. Urdu was not the official language of the Sultanate of Delhi.
Arabic is a Semitic language that was first spoken in the Arabian Peninsula. It is the official language of Saudi Arabia, the United Arab Emirates, and Qatar. Arabic was not the official language of the Sultanate of Delhi.
Hindi is an Indo-Aryan language that is spoken in India and Nepal. It is the official language of India. Hindi was not the official language of the Sultanate of Delhi.
The Sultanate of Delhi was a Muslim empire that ruled over much of the Indian subcontinent from the 13th to the 16th centuries. The empire was founded by Qutb-ud-din Aibak in 1206. The Sultanate of Delhi reached its peak under the rule of Alauddin Khalji in the 14th century. The empire declined in the 16th century and was finally overthrown by the Mughal Empire in 1526.