Who among the following ancient scholars was a proponent of grammarian…

Concept

Classical Indian philosophy is traditionally organized into schools identified by their primary concern and principal exponent. Among these, the six orthodox (astika) schools -- Nyaya, Vaisheshika, Samkhya, Yoga, Mimamsa, and Vedanta -- address logic, metaphysics, or liberation, while a distinct grammarian (Vyakarana) tradition treats language, meaning, and grammar itself as the object of philosophical inquiry.

Application

Bhartrihari (circa 5th century CE) is the principal figure of the Vyakarana tradition. His treatise the Vakyapadiya develops the philosophy of language, including the Sphota theory of meaning and the concept of Shabda-Brahman, establishing grammar as a path to philosophical insight. This makes Bhartrihari the scholar associated with the grammarian tradition among the options given.

Contrast

• Gautama founded the Nyaya school, which systematizes logic and the valid means of knowledge (pramanas) -- a school of epistemology, not grammar.

• Kanada founded the Vaisheshika school, an atomistic theory that classifies reality into substance categories (dravya, guna, karma) -- a school of metaphysics, not grammar.

• Ishwarkrishna authored the Samkhyakarika, systematizing the Samkhya school's dualism of purusha (consciousness) and prakriti (matter) -- a school of cosmology, not grammar.

Hence, Bhartrihari is the scholar who was a proponent of the grammarian tradition.