Who was the first Muslim ruler to conquer South India?
A. Alauddin Khalji
B. Sher Shah
C. Babur
D. Aurangzeb

Hint: The Second Battle of terrain, in which Prithviraj Chauhan was defeated by Mu’izz al-Din laid the foundations of Muslim rule in northern India. Many Muslim rulers fought against Indian rulers to capture the capital Delhi and further Southern India as they aimed to capture whole India.

Complete Step by Step answer: Muslim invasion in India began in the beginning of 13th century which was the period of Delhi Sultanate in which five dynasties ruled in Delhi or India. These were the slave dynasty, Khilji dynasty, Tughlaq dynasty, Sayyid dynasty and Lodi dynasty. From then, the Mughal empire exceeded towards the south.
It was under Alauddin Kalji, the Khilji dynasty succeeded in bringing the northern half of south India for the first time. He conquered Gujarat, Chittor, Ranthambore, Malwa and Deccan. His slave general Malik Kafur obtained a considerable amount of wealth from Devgiri, Warangal, Dwarasamudra. He undertook large scale reforms in military and administration to maintain a large army with some revenue reforms. In architecture, he constructed Hauz-i-Alai (Hauz khaz), Alai Minar, Alai Darwaza and so on.
Sher Shah, Babur and Aurangzeb later ruled over Indian subcontinent introducing many religious and administrative reforms which helped them to conquer till British came to India.
Looking at the options given:
Option A. Alauddin Khalji is the correct answer as he was the first one who ruled over South India by conquering the area of Deccan region.
Option B. Sher Shah ruled from 1538 to 1545 and founded the Suri Empire in India with its capital Sasaram in Bihar. His rule was confined to northern India. Thus, this is an incorrect option.
Option C. Babur was the founder of the Mughal Empire and initially conquered the Northwestern region of India. This is an incorrect option.
Option D. Aurangzeb ruled over the entire Indian subcontinent including South India but he was not the first one to rule over here. This is an incorrect option.

Note: Both Aurangzeb and Alauddin Khaliji ruled over South India but their time varied. So, don’t get confused between them. Aurangzeb was a Mughal Emperor whereas Alauddin Khaliji was a Delhi Sultan.