What formed the western border of the disputed land before the war french and indian?

In February 1763, the British signed the Treaty of Paris with France; bring to an end the 7 years’ war (also called the French and Indian war). This war had been fought over disputed territory in the Ohio River valley. This is because the border between the British and French possessions were not well defined. And one disputed territory was the upper Ohio River Valley. In an attempt to strengthen their claim on the territory, the French constructed a number of forts in this region, thus leading to the war.

a

explanation:

b is the answer i am assuming