The correct answer is D) His plan would disrupt the checks and balances of the government.
"Court-packing" was a plan by president Franklin D. Roosevelt to expand the Supreme Court. Roosevelt wanted to add more justices to the Supreme Court to ensure that the Supreme Court would support his New Deal policies. After all, the Supreme Court is the part of the federal government that determines what laws are constitutional and unconstitutional.
If FDR had the power to pick a significant amount of Supreme Court justices, it would throw off the system of checks and balances. This is because the Supreme Court would be dominated by people he put into office.