Answer:
The increasing demand for high-value goods and manufactures in Afro-Eurasia is the correct answer.
Step-by-step explanation:
As explained in the question, Madmun ibn al-Hassan was an important Jewish merchant. Aden has always been important for the region due to its characteristic as a port.
Letter C is the correct option since the merchandise discussed in the letter is not very common. It is important to remember that the prices for those goods was very high and so the demand was. The amount of them only emphasizes the increasing demand in Afro-Eurasia.