Option c is the correct answer. Amir Khusrau served as courtier, royal poet and court musician under Turkish Sultans. Hindustani is based on an early dialect of Hindi, known by linguists as Khari Boli, which originated in Delhi. Khusrau gave to Hindi its first Khari Boli compositions. It was used throughout the Mughal empire, especially by merchants who needed a common commercial language. He is considered the "father of Hindi Khari Boli", the standard form of Hindi that is spoken today.