The correct answer is: a) Assamese.
Assamese is the primary medium of instruction in most schools in Assam. It is the official language of the state and is spoken by the majority of the population. English is also taught in schools, but it is not the primary medium of instruction. Bengali and Hindi are minority languages in Assam and are not used as the medium of instruction in most schools.
Assamese is a member of the Indo-Aryan language family and is closely related to Bengali and Oriya. It is written in the Assamese script, which is derived from the Brahmi script. Assamese literature dates back to the 13th century and includes a rich tradition of poetry, drama, and fiction.
Assamese is a beautiful and expressive language that is full of life and color. It is the language of the Assamese people and is a vital part of their culture.