Why was cornwallis unable to be reinforced by british ships entering chesapeake bay?

A french fleet of 24 ships in Chesapeake Bay was able to seal off the waters to the east. Cornwallis would also not be reinforced by British ships coming down the York River from the West because French troops covered the area and the west doesn't lead to the ocean

4 copper and gold, the california gold rush is why im pretty sure.

the correct answer is:

true

i am an online student and after i submit my quizzes, it gives me the correct answers to any that i may have missed. the answer to this question is true