The correct answer is A. Ashoka.
Ashoka the Great was the third emperor of the Mauryan Empire, reigning from 272 to 232 BCE. He is known for his military conquests, but also for his Buddhist reforms and his promotion of non-violence.
Ashoka sent his missionaries to many parts of the Indian subcontinent, as well as to other countries such as Sri Lanka, Tibet, and China. These missionaries were responsible for spreading Buddhism and Ashoka’s message of peace and non-violence.
The other options are incorrect. Chandragupta was the founder of the Mauryan Empire, but he did not send missionaries to Ladakh. Bindusara was Chandragupta’s son and Ashoka’s father, but he also did not send missionaries to Ladakh. Samprati was Ashoka’s grandson, but he was not emperor during the time that Buddhism was first introduced to Ladakh.