Answer: The cost of the French and Indian War
Explanation: A is incorrect because the high price of tea is due to those taxes. B is incorrect because most of the red uniforms weren't manufactured until the Revolutionary War, which was yet to come. C is incorrect because the intolerable acts came into place as a punishment for the colonist's actions in the Boston Tea Party. So the answer is D, which makes sense because that was a very costly war for the British.