To develop a fair and effective counterclaim to the argument for Washington, DC statehood based on the principle of "taxation without representation," the most helpful evidence would be:
C. As the capital of the United States, Washington, DC was never meant to be a state because the Founding Fathers feared its people would have too much influence.
This option directly addresses the historical context and intentions behind the establishment of Washington, DC as a federal district, setting it apart from other states. It provides an argument that aligns with the original framework of the United States and the concerns of the Founding Fathers regarding the unique status of the capital. This can effectively challenge the notion that DC should have the same representation as other states.