Option b is the correct answer. Statement 1 is correct - Shankara is renowned for espousing a form of Vedanta called Advaita. Advaita Vedanta emphasizes the non-dual nature of reality, asserting that the individual self (Atman) and the ultimate reality (Brahman) are essentially one. Statement 2 is correct - Shankara elaborated on the philosophy of Gaudapada, who was his predecessor. Gaudapada's main work, the Mandukya Karika, served as a foundation for Shankara's Advaita Vedanta philosophy. Statement 3 is correct - Shankara aimed to demonstrate that the Upanishads (ancient philosophical texts) and Brahmasutras (scriptures on the nature of Brahman) contain a unified and systematic philosophy. He provided commentaries on these texts to elucidate their underlying teachings. Statement 4 is incorrect - Shankara did not found the Amanaya Mathas. The mathas, also known as monastic centers, were established by his disciples to preserve and propagate his teachings.