The correct answer is option 1 - Ashoka. The Sanchi Stupa, located in Madhya Pradesh, India, was built by Ashoka, the Mauryan emperor, in the 3rd century BC. Ashoka was a devout follower of Buddhism and played a key role in spreading the teachings of Gautam Buddha throughout his empire. The Sanchi Stupa is one of the oldest stone structures in India and is considered an important Buddhist pilgrimage site. It was originally constructed to house the relics of Gautam Buddha and has since been expanded and renovated by different rulers over the centuries. The stupa is known for its intricate carvings and iconic dome structure, which is a symbol of Buddhism.