Option a is the correct answer. Patanjali was an ancient Indian sage who is regarded as the founder and propagator of Yoga Darshan, or the classical school of Yoga philosophy. Yoga Darshan is one of the six orthodox systems of Indian philosophy, which aims to achieve liberation from suffering and ignorance through the practice of physical, mental, and spiritual disciplines. Patanjali compiled and codified the teachings of Yoga Darshan in his famous work called Yoga Sutras, which consists of 196 aphorisms that describe the theory and practice of Yoga.