Option a is the correct answer. According to Advaita Vedanta, mukti can be obtained by gyana (knowledge). Gyana is the realization of one's true self (atman) as identical with the supreme reality (brahman). It is the direct and intuitive knowledge that transcends the duality of subject and object, and dispels the ignorance (avidya) that causes bondage to the cycle of births and deaths (samsara). Gyana is not acquired by mere intellectual study, but by the grace of a guru and the practice of meditation (dhyana). It is the highest of the three paths to liberation (moksha), along with bhakti (devotion) and karma (action).