The correct answer is option 2, 1206 AD. The rule of the Delhi Sultanate began in this year.
Option 1, 1106 AD, is incorrect. The Delhi Sultanate did not begin in this year.
Option 3, 1306 AD, is also incorrect. This is not the correct starting year for the Delhi Sultanate.
Option 4, 1406 AD, is incorrect. The Delhi Sultanate did not begin in this year either.
It is important to remember that the Delhi Sultanate refers to a period of Muslim rule in Delhi and northern India. It began when Qutb-ud-din Aibak established the first sultanate after the defeat of the last Hindu ruler in the Battle of Tarain in 1192 AD. This marked the beginning of the Muslim rule in the region.