The correct option is D Upanishads
The Later Vedic literature includes the Sutras, the Vedangas, the Upavedas, the Darshanas, the Puranas, the Dharmashastras, and the Great epics or the Mahakavyas.
Whereas, the early Vedic literature comprises the four principal Vedas, the Brahmanas, the Aranyakas, and the Upanishads.