When did the Indian Independence Act receive the British royal assent?

Correct option is A

The British Prime Minister, Clement Attlee, introduced the Indian Independence Bill in the House of Commons on 4 July 1947. It was passed by both the houses of the British Parliament on 15 July 1947. It received Royal Assent on 18 July 1947.
The Indian Independence Act repealed the Government of India Act of 1935 and ended British suzerainty over the princely states, giving them the option to join either India or Pakistan or to remain independent.