Kevin, a 69-year-old single taxpayer, received $20,000 in social security benefits in 2015. He also earned $12,000 in wages and $6,000 in interest income, $4,000 of which was tax-exempt. What percentage of Kevin's benefits will most likely be considered taxable income?

A) None

B) Up to 50%

C) Up to 85%

D) Up to 100%

Note: Option B) Up to 50% is incorrect answer in my test