The correct option is D People started using nishka, satamana, krishmana to buy goods.
The Later Vedic society became more complex. The earlier Varna system was replaced by a complex caste system. The status of women degraded. For trade, regular coins like Nishka, Satamana and Krishmana were used as the medium of exchange replacing the barter system of the early Vedic period. Gods like Indra, Varuna, Surya, Prithvi, and Agni lost their prominence and were replaced by Brahma, Vishnu, Shiva, Ganesha, Parvati, Rama, Krishna etc. During the later Vedic period, the religious rituals, ceremonies became complex and the importance of Brahmana grew. At the same time, the king became the centre of power, while the authority of sabha, samiti, and purohit diminished.