Option b is the correct answer. A. Nyaya Darshan: This is a school of Indian logic and epistemology that holds that logical thinking is the means of attaining salvation. Nyaya Darshan uses inference, analogy, and testimony as valid sources of knowledge, and employs a system of syllogisms to establish valid arguments. Nyaya Darshan aims to refute the errors of other schools and establish the existence of the self, God, and liberation. B Mimamsa Darshan: This is a school of Indian hermeneutics and ritualism that holds that performing Vedic rituals is the means of attaining salvation. Mimamsa Darshan interprets the Vedas as eternal and authoritative sources of knowledge, and prescribes the rules and methods for performing sacrifices and ceremonies. Mimamsa Darshan believes that by fulfilling one's duties and obligations according to the Vedas, one can attain happiness and liberation. C. Sankhya Darshan: This is a school of Indian dualism and metaphysics that holds that acquisition of real knowledge is the means of attaining salvation. Sankhya Darshan posits that reality consists of two independent principles: purusha (consciousness or spirit) and prakriti (nature or matter). Sankhya Darshan aims to achieve liberation (kaivalya) by realizing the distinction between purusha and prakriti, and detaching oneself from the bondage of prakriti. D. Vedanta Darshan: This is a school of Indian monism and philosophy that holds that knowledge of self is the means of attaining salvation. Vedanta Darshan is based on the Upanishads, which are the philosophical portions of the Vedas. Vedanta Darshan teaches that the ultimate reality is Brahman, which is identical to the self (atman). Vedanta Darshan aims to achieve liberation (moksha) by realizing one's true nature as Brahman, and overcoming ignorance (avidya) and illusion (maya).