Answer : 1. "I- (c), II- (d), III- (b), IV- (a)"
Explanation :

Ramanuja is the main proponent of Vishishtadvaita philosophy. The philosophy itself is considered to have existed long before Ramanuja's time. Vishishtadvaita is one of the most popular schools of the Vedanta school of Hindu philosophy. Vedanta literally means the end of the Vedas. Vishisht Advaita is a non-dualistic school of Vedanta philosophy. The Dvaita or “dualist” school of Hindu Vedanta philosophy originated in 13th-century South India with Sri Madhvacarya (Madhva). Madhva, who considered himself an avatar of the wind-god Vayu, argued that a body of canonical texts called the “Vedanta” or “end of the Veda” taught the fundamental difference between the individual self or atman and the ultimate reality, brahman. Nimbarka, a Telugu Brahman, yogi, and philosopher, teaches the Vaishnava bhedabheda theology of Dvaitadvaita or dualistic non-dualism. The Nimbarka Sampradaya, also known as the Hamsa Sampradaya, and Sanakādi Sampradāya, is one of the four Vaiṣṇava Sampradayas. Shuddhadvaita and vishishtadvaita is the "purely non-dual" philosophy propounded by Vallabhacharya (1479-1531 CE), the founding philosopher and guru of the Vallabhā sampradaya ("tradition of Vallabh") or Pustimarg ("The path of grace"), a Hindu Vaishnava tradition focused on the worship of Krishna. Vallabhacharya's pure form (nondualist) philosophy is different from Advaita. The Shrinathji temple at Nathdwara, and compositions of eight poets (aṣṭachap), including Surdas, are central to the worship by the followers of the sect.