Susan, single, is 64 years old and is contemplating applying to receive her Social Security benefits when she turns 65. Which of the following statements regarding Social Security benefits is correct?

a) Social Security benefits are always tax-free.

b) Up to 85% of Social Security benefits are taxable if other income, including tax-exempt interest, plus 100% of her Social Security benefit is more than $34,000.

c) Social Security benefits are 50%taxable if her other income, including tax-exempt interest income, is more than $25,000.

d) Social Security benefits are not taxable if her other income, which includes any tax-exempt interest, plus 1/2 of the Social Security benefit, is $25,000 or less.