The correct answer is: A) English.
Malayalam is the official language of Kerala, but English is the primary medium of instruction in most government schools. This is because English is seen as a more useful language for employment and higher education. However, Malayalam is still taught as a subject in all schools, and students are expected to be able to speak, read, and write both languages.
Option B is incorrect because Malayalam is not the primary medium of instruction in most government schools. Option C is incorrect because Hindi is not an official language of Kerala. Option D is incorrect because a mix of Malayalam and English is not the primary medium of instruction in most government schools.