John is receiving $1,000 each month from Social Security, and he works at a local store as a part-time worker to earn extra $1,000 each month. He has very small amounts (less than $1,000 a year) of interest and dividends income. He is a single filer. How much should he pay taxes on his Social Security benefits?

a.   No taxes on Social Security benefits because the combined income is less than $25,000 a year.

b.   25% taxes on Social Security benefits because the combined income is less than $25,000 a year.

c.   50% taxes on Social Security benefits because the combined income is less than $25,000 a year.

d.   5% taxes on Social Security benefits because the combined income is less than $25,000 a year.

e.   100% taxes on Social Security benefits regardless of the combined income level.