Ibn Battuta was appointed as the Qazi (judge) of Delhi by:

Ibn Battuta (1304-1368/69) was a famous traveller from Tangier in Morocco. Over about 30 years, he travelled around 1,20,000 kilometres across North Africa, the Middle East, Central Asia, India, South-east Asia and China, more than any other traveller before modern times.

Ibn Battuta reached India in 1333, crossing the Hindu Kush and arriving through Sindh. At that time, Sultan Muhammad bin Tughlaq (ruled 1325-1351) was known for welcoming learned foreigners. He was impressed by Ibn Battuta's knowledge of Islamic law and appointed him the Qazi (judge) of Delhi, with a large salary. Ibn Battuta stayed in India for several years. In 1342, the Sultan sent him as his ambassador to the Mongol (Yuan) emperor of China. On the way, after various adventures, he spent time in the Maldives, where he also served as a judge, and in Sri Lanka.

Ibn Battuta's travel account is called the "Rihla" (meaning "journey"). He dictated it after returning to Morocco, to the scholar Ibn Juzayy, in 1355. It was written in Arabic. The Rihla gives a lively description of the court of Muhammad bin Tughlaq, the cities of Delhi and Daulatabad, the postal system (dawa and ulaq, foot and horse runners), the use of the betel leaf and coconut, slavery, and the social and economic life of India in the 14th century.

Muhammad bin Tughlaq himself is remembered for his ambitious but poorly executed experiments, such as shifting the capital from Delhi to Daulatabad, introducing token currency in copper and brass, raising taxes in the Doab and planning expeditions to Khurasan and Qarachil.

Why not the other options?

• ✗Alauddin Khalji ruled before Ibn Battuta arrived.
• ✗Firoz Shah Tughlaq succeeded Muhammad bin Tughlaq in 1351, after Ibn Battuta had left.
• ✗Ghiyasuddin Tughlaq died in 1325, before Ibn Battuta's arrival.