Option b is the correct answer. Charvaka is a school of Hinduism that holds that only perception is a reliable source of knowledge. Charvaka is also known as Lokayata, which means "worldly" or "materialistic". Charvaka rejects the authority of the Vedas, the existence of the soul, the concept of karma and rebirth, and the existence of God. Charvaka believes that only what can be perceived by the senses is real, and that everything else is either false or uncertain. Charvaka advocates a hedonistic and pragmatic way of life, and urges people to enjoy the pleasures of the world without fear or guilt.