Which of the following statements is true regarding involuntary wage attachments?

a. Garnishment deductions are only 20% of disposable pay by federal law.
b. Federal tax levies continue until the deduction is released by the IRS.
c. The priority on wage attachments is (1) child support, (2) creditor garnishment, and (3) federal tax levy.
d. Voluntary deductions are used to calculate the employee's disposable pay.