The correct answer is: A. Nimbarka
Nimbarka (1137-1230) was a Hindu philosopher who founded the Dvaitadvaita school of Vedanta. He is best known for his commentary on the Brahma Sutras, called the Vedanta-Parijatasourabha. In this commentary, Nimbarka argues that Brahman, the ultimate reality, is both one and many. He also argues that there are two paths to liberation: knowledge and devotion.
Ramanuja (1017-1137) was a Hindu philosopher who founded the Visistadvaita school of Vedanta. He is best known for his commentary on the Brahma Sutras, called the Sri Bhashya. In this commentary, Ramanuja argues that Brahman, the ultimate reality, is both one and many. He also argues that the path to liberation is through devotion to Vishnu.
Madhva (1199-1278) was a Hindu philosopher who founded the Dvaita school of Vedanta. He is best known for his commentary on the Brahma Sutras, called the Brahma Sutra Bhashya. In this commentary, Madhva argues that Brahman, the ultimate reality, is one and that the world is real and separate from Brahman. He also argues that the path to liberation is through knowledge of Brahman.
Vallabhacharya (1479-1531) was a Hindu philosopher who founded the Pushtimarga school of Vaishnavism. He is best known for his commentary on the Bhagavad Gita, called the Tattva-Traya-Viveka. In this commentary, Vallabhacharya argues that Krishna is the supreme deity and that the path to liberation is through devotion to Krishna.