Option a is the correct answer. Nagarjuna was not a proponent of the Bhakti cult. He was a Buddhist philosopher who lived in the 2nd century CE and founded the Madhyamaka school of Mahayana Buddhism. He is famous for his doctrine of emptiness (shunyata) and his use of logical reasoning (pratityasamutpada) to refute metaphysical claims. Important Tips Some of the famous proponents of the Bhakti cult were: The Alvars and Nayanars of South India who worshipped Vishnu and Shiva respectively The Varkari saints of Maharashtra such as Dnyaneshwar, Namdev, Tukaram, and Eknath who venerated Vitthal, a form of Krishna The Nirguna saints of North India such as Kabir, Ravidas, Nanak, and Dadu who rejected idolatry and caste distinctions and advocated a formless God The Saguna saints of North India such as Ramananda, Ramanuja, Vallabhacharya, Chaitanya, and Surdas who followed the Vaishnava tradition and expressed devotion to Rama or Krishna The Shakti saints of Bengal and Assam such as Ramprasad Sen, Kamalakanta Bhattacharya, and Sankaradeva who revered the Goddess as the supreme power