Michelangelo, Inc. reported net income for the year of $22,500. During the year, Michelangelo had federal income tax expense of $4,200, penalties of $800, business meals with clients of $3,000, and received $2,000 interest on a municipal bond. How much was Michelangelo's taxable income?

a. $18,000

b. $31,000

c. $14,000

d. $27,000