On what basis is it held that on the east the province of Vanga (part of modern Bengal) formed part of the Mauryan empire?
(a) Discovery of Ashokan edicts in this part of Bengal
(b) Tamralipti, the principal port of the area, was one of the most important maritime centres during the Mauryan period
(c) Megasthenes’ Indica mentions Chandragupta’s conquest of the region
(d) Buddhist traditions associate Ashoka with propagation of Buddhism in Bengal