The correct answer is: A. Sanskrit.
Katyayanaprakarna is a book on Sanskrit grammar written by Katyayana, a Sanskrit grammarian who lived in the 2nd century BCE. The book is a commentary on the Ashtadhyayi, a Sanskrit grammar treatise written by Panini. Katyayanaprakarna is considered to be one of the most important works on Sanskrit grammar.
Pali is a Middle Indo-Aryan language that was used in ancient India. It is the language of the Theravada Buddhist scriptures. Pali is closely related to Sanskrit, but it is not the same language.
Tamil is a Dravidian language that is spoken in India and Sri Lanka. It is the oldest living language in the world. Tamil is not related to Sanskrit.
Telugu is a Dravidian language that is spoken in India. It is the second most spoken Dravidian language after Tamil. Telugu is not related to Sanskrit.