Portuguese mariners succeeded in building a trading-post empire early in the sixteenth century for all of the following reasons except: a) the ruthless policies of naval commander afonso d'alboquerque. b) the head start that portugal enjoyed over other european powers in the exploration of the indian ocean. c) the use of heavy artillery to overpower other craft and onshore sites. d) the portuguese control of strategic ports such as hormuz and melaka. e) the superiority of the portuguese navy over english and dutch forces.