Which of the following could not be a leg of the triangular trans-atlantic trade?
a. manufactured goods sold to africans
b. african slaves delivered to the americas
c. barbados rum sold to england
d. mexican silver delivered to manila

It would be "d. Mexican silver delivered to Manila," that could not be a leg of the triangular trans-Atlantic trade, since Manila was nowhere along these well-established trade route. 

The  pan-african movement  was an "emotional, cultural, psychological and ideological  movement  that began among the  african  dispora in the western hemisphere, for a closer  purpose, so that  african  people could feel secure, attain political, economic as well as psychological power visa vis other races or world regions" .