The answer is: C) camel from Arabia.
Since about 1000 BC, there has been trade between the North and South of the Saharan desert. The introduction of the camel as means of transportation about the eleventh century helped transform the Tran-Saharan trading activity an organised activity, strengthening what is today known as the caravan trade routes. This animal chosen for its strength and preparedness to withstand the harsh desert climatic conditions also served in the Trans-Saharan caravan routes where African slaves from sub-Saharan region were taken across the Sahara into North Africa and Arabian cities to work as domestic helps, laborers and soldiers.