Final answer:
The point of the argument is that the U.S. income tax system needs to be reformed, with supporting statements illustrating specific problems and issues with the current system.
Step-by-step explanation:
The point of the argument in this group is statement c, "The U.S. income tax system needs to be reformed." This statement presents the main idea or goal of the argument, while the other three statements provide support for this point. Statement a provides an example of a problem with the current system, statement b highlights a specific issue related to tax fairness, and statement d identifies another aspect of the current tax system that may need reform. By addressing these supporting statements, the argument strengthens its claim that tax reform is necessary for a fairer system.