Suppose There Is a 20% Tax on the First $15,000

Multiple Choice

Suppose there is a 20% tax on the first $15,000 of taxable income,a 30% tax on taxable income above $15,000 until $30,000,and a 40% tax on all taxable income above $30,000.There is a $3,000 exemption per person.What is the marginal tax rate for a single mother making $35,000 who has one child?

A) 20%
B) 30%
C) 31.7%
D) 40%