Which among the following statements explains the downfall of the Mauryan empire?

A Rise of Brahmana dynastic, financial crisis, oppressive measures of the mahamatras and neglect of the north-west frontier

B Ashoka’s deliberate and systematic policy of acculturation through the appointment of Dharmamahamatras

C The spread of material culture, inscription and punchmarked coins in Bangladesh, Orissa Andhra and Karnataka

D Pushyamitra Sunga killed the last Maurya king Brihadratha in 185 B.C.