Which of the following statements about the philosopher Shankara is /are true? 1. Shankara espoused a form of Vedanta called Advaita. 2. He elaborated on the phiosophy of Gaudapada. 3. Shankara tried to demonstrate that the Upanishads and Brahmasutras contain a unified, systematic phiosphy. 4. Shankara founded the Amanaya Mathas. Select the correct answer using the code give below (a) 1 and 2 only (b) 1,2 and 3 (c) 3 and 4 (d) 4 only