For the first passage about Ghana's rulers, the most reasonable inference is:
They were smart businessmen who took advantage of opportunities.
This choice aligns with the idea that the rulers were looking for ways to capitalize on the presence of traders in their lands by implementing taxes.
For the second question about Arabian merchants in the 700s A.D., the best response is:
spreading new technology among Asia, Africa, and Europe.
This choice reflects the significant role that Arabian merchants played in facilitating trade and the exchange of ideas and technologies during that time.