Answer:
Correct answer is c. He retreated to Yorktown where he was trapped.
Step-by-step explanation:
Option C is the correct one as no one event during Revolutionary War had such importance as the battle of Yorktown had. Cornwallis retreated to Yorktown where he was surrender by stronger Continental Army, supported by France. He was forced to surrender and this battle marked the end of British hopes that they will retrieve colonies.
All other options are therefore false, as they don't have significance as this battle had.