Option a is the correct answer. Muinuddin Chishti was fond of devotional music, especially Qawwali, which is a form of Sufi music that involves singing, playing instruments, and clapping. He believed that Qawwali could induce a state of ecstasy (wajd) in which the listener could experience the divine presence and love. He encouraged his disciples and followers to attend musical assemblies (sama) at his khanqah (Sufi lodge) and participate in the remembrance of God through Qawwali. He also had a close relationship with Amir Khusro, a renowned poet and musician who was his disciple and biographer and who is credited with developing many genres and styles of Qawwali.