The correct answer is option 4: Persian. The court language of the Mughals, who ruled over India from the 16th to the 19th century, was Persian. Persian was widely used in the Mughal courts for administrative purposes, official correspondence, and literary and poetic works. It served as the language of diplomacy and was also spoken by the elite and educated classes. Persian had a significant influence on the development of Urdu, which emerged as a blend of Persian and Hindi. While Urdu eventually became the language of the common people, Persian remained the language of the Mughal court and the educated elite. It is important to note that Hindi, Urdu, and Arabic were also important languages during the Mughal period, but Persian took precedence as the court language.