Who, before going to the gallows, had expressed his desire for keeping his ashes intact till India is reunited and throwing them into the Indus after the reunification has been achieved?

Nathuram Godse

The correct answer is Option 4- Nathuram Godse

The person who expressed the desire to keep his ashes until India's reunification is  Nathuram Godse.  He believed in a united India, also known as Akhand Bharat.