The correct options are
A Fertile land
C Proximity to the sea
Coastal areas had fertile land fit for cultivation of crops, which were important to produce trade goods. The availability of gold was a feature of these coastal areas because of the traders that passed through. This, however, was not a contributing factor in making coasts so important for trade. The proximity to the sea made the coasts witness the arrival of traders from far off lands by means of their ships. Additionally, tax collection in these areas was high owing to the large volume of trade.