Most Buddhist texts were written in Pali, which is the correct answer. Pali is a language that belongs to the Indo-Aryan language family and is closely related to Sanskrit. It was the language used by the Theravada school of Buddhism, which is prevalent in Southeast Asian countries like Sri Lanka, Thailand, and Myanmar.

Sanskrit, option 1, is also an important language in Buddhism, especially in Mahayana Buddhism, but it was not the language in which most Buddhist texts were written.

Magadhi, option 2, is an ancient language that was spoken in the region of Magadha in ancient India, but it was not the primary language used for Buddhist texts.

Prakrit, option 3, is a general term for a group of Middle Indo-Aryan languages spoken in ancient India. Although Prakrits were used for some Buddhist texts, Pali was the most commonly used language for Buddhist scriptures.