The correct option is B Armaments and Ship building
Trade and enterprise during the Mauryan period were public-private affairs: the state could own and engage in business activities just like ordinary citizens could. The royal revenue was drawn from taxes (and war booty). Additionally, the king owned timber land, forest land, hunting groves, and manufacturing facilities, and their surplus was sold off. The state had monopoly over coinage, mining, salt production, arms manufacture, and boat building.