The correct answer is - Mongols.
The Islam in India was brought earlier than 1100 AD, by Arab merchants, but that was on a small scale in small areas. The big introduction of Islam in India happened in 1100 AD with the invasion by the Mughals.
The Mughals were people that had mixed origin, the aristocracy being mostly of Mongol descent initially, of the blood line of Genghis Khan, with some Turkic admixture, most of the ordinary people were a mixture of Mongols, Turkic people, and Iranian people. Anyway, the roots of the empire are often considered to be Mongol ones.
The Mughals had accepted the Islam as their religion. When they invaded India, they also brought and imposed their religion. They reign in India was for several centuries, so they managed to have a big effect on the religious map of the region, where large areas of northern India are predominantly Muslim, and Pakistan is almost entirely Muslim.