Question

Which of the following events led to the decline of trans-Saharan trade?
A. the arrival of Columbus to the Caribbean
B. the establishment of Portuguese ports on the west African coast
C. the Reconquista
D. the expansion of Muslim empires in the Mediterranean

Answer 1

the answer is B: the establishment of Portuguese ports on the west African coast

Answer 2

B. the establishment of Portuguese ports on the west African coast 
let me know if its right