Correct answer: D) The American troops surrounded the British lines and began to shell them, while the French Navy blocked any chance for their escape by blockading the York River.
Further details/context:
Britain's general, Lord Cornwallis, had retreated to the Yorktown peninsula in Virginia in June 1781. He hoped for rest and recovery for his army, which was struggling against the American revolutionary fighters. General George Washington amassed all available troops to besiege and attack the British at Yorktown in the fall of 1781, which turned out to be the final, decisive battle of the American Revolution. The presence of a 34-ship French battle fleet did much to help in bombarding and defeating the British at Yorktown also.