The first invasion of India by Sultan Mahmud Ghazni was in

The first invasion of India by Sultan Mahmud of Ghazni took place in the year 1000 AD. He was the ruler of the Ghaznavid Empire, which was centered in the region of present-day Afghanistan. Mahmud of Ghazni is famously known for his multiple raids into the Indian subcontinent, which were aimed at acquiring wealth and establishing his influence.

During his invasions, Mahmud targeted various parts of northern India, particularly the region that is now modern-day Pakistan and northern India. His raids were marked by plundering and looting of temples and cities, including the famous Somnath Temple. These invasions had a significant impact on the history and cultural heritage of the Indian subcontinent.

Therefore, the correct option is Option C: 1000 AD, which represents the year of the first invasion of India by Sultan Mahmud of Ghazni.