The historian Barani didn`t consider the state in India under the Delhi Sultans as truly Islamic due to Sultan supplementing the Muslim law by framing his own regulations.

Option 1 surfaces from the fact that majority population not following Islam doesn`t necessarily make the State less Islamic as it is about the governing rules and laws and not about the religious makeup of the population.

Option 2 can be ruled out as the disregard of Muslim theologians wouldn`t necessarily mean the state as non-Islamic. It might affect religious interpretation but doesn`t change the Islamic nature of the state.

Option 4 mentions religious freedom accorded to non-Muslims. While Islamic states can enforce Islamic principles, they can also allow religious freedom to others, making this point irrelevant to whether the state is Islamic or not.

In contrast, option 3 accurately represents why Barani may not have considered the India under Delhi Sultans as truly Islamic. The Sultan supplementing Islamic law with his own regulations inherently changes the Islamic nature of the state.