Question

why was it a mistake for general cornwallis to camp his army at yorktown?
yorktown was too far away from other british forces to be effectively resupplied.
yorktown was on a peninsula and hard to resupply.
yorktown was on a peninsula and could be surrounded.

Explanation:

Yorktown's peninsular location made it vulnerable to being surrounded by the combined American and French forces, which was a major strategic flaw for Cornwallis' army. Resupply issues were secondary to the threat of encirclement in determining the strategic mistake.

Answer:

Yorktown was on a peninsula and could be surrounded.