Sally Is a Single Individual

Sally is a single individual.In 2016,she receives $10,000 of tax-exempt income in addition to her salary and other investment income of $100,000.Sally's 2016 tax return showed the following information: ​
Which of the following statements concerning Sally's tax rates is (are) correct?
I.Sally's average tax rate is 19.4%.
II.Sally's average tax rate is 25.0%.
III.Sally's marginal tax rate is 25%.
IV.Sally's marginal tax rate is 28%.
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A) Statements I and III are correct.
B) Statements I and IV are correct.
C) Statements II and III are correct.
D) Statements II and IV are correct.
E) Only statement IV is correct.