Answer:
Items are being ranked from lowest (1) to highest (6)-
1. Letter ruling.
2. Proposed Regulation.
3. Revenue Ruling.
4. Interpretive Regulation.
5. Legislative Regulation.
6. Internal Revenue Code.
Step-by-step explanation:
Federal tax law system: The term "federal tax law system" is described as a system that is being administered through the IRS that is responsible for collecting money on the basis of "earned income". Federal income tax is supposed to be collected by a "withholding process" wherein the employer tend to deduct tax from every employee payroll.
In the question above, the given statement represents the answer as c-f-d-a-b-e.