4. Which is the best conclusion to draw from this passage? "There was so much salt in the Sahara, that people in Taghaza, in the central part of the desert, built homes out of blocks of salt. But in the savanna, several hundred miles south, salt was so scarce that it was worth its weight in gold. In the kingdom of Ghana, merchants paid one pound of gold for one pound of salt." A. The even distribution of natural resources promotes trade B. The surplus of a given natural resource affects its value C. The scarcity of a given natural resource affects its value D. The uneven distribution of natural resources promotes trade