Which weapon brought significant changes to warfare during the hundred years' war?

a.
longbow

b.
crossbow

c.
sword

d. spear

It was the crossbow. Because they could fight with some distance in the middle and it was more deathly than the longbow.

Question: Which weapon brought significant changes to warfare during the Hundred Years' War?  

Options:

A.  longbow

B.  crossbow

C.  sword

D. spear

The correct answer is option: A)  longbow .

Explanation: In the year 1337-1453, The Hundred Years' War used the longbow as a very important weapon. It became legend after it played a very important role in securing the great English victories at Crécy, Poitiers and Agincourt.  At the Battle of Sluys in 1340, 20,000 English soldiers defeated 60,000 French soldiers by using longbows. This battle serves as proof of how effective the longbow was as a weapon.

bibliography and citations to credit the sources hope this you if not my deepest of apologize ^w^

the answer is 250 percent.