What Event Prompted the Portuguese and Others to Find a New

What event prompted the Portuguese and others to find a new avenue to the sources of spices?

A) The collapse of Indonesia in 1433 sparked a rush to enter the spice market.
B) The Venetians ended their exclusive trade treaty with the Ottoman Turks in 1445.
C) The fall of most of the Italian states to other European powers in the late fifteenth century allowed the Portuguese to expand.
D) After the Ottomans conquered Constantinople in 1453, they controlled the spice trade and could raise taxes at will.
E) The invention of sailing ships in the late fifteenth century encouraged more trade.