Which of the following statements is correct regarding Roth IRAs?

a. The contributions are deductible if an unmarried taxpayer is not an active participant in an employer-sponsored retirement plan.

b. Only the taxable portion of amounts distributed from a Roth IRA are subject to the early withdrawal penalty.

c. Withdrawals from a Roth IRA prior to age 59½ are taxable.

d. A 10% penalty applies to excess contributions.