can someone please tell me why the last answer is wrong?

Determine the retirement savings contributions credit in each of the following cases. Use Table 9-2. X Answer is complete but not entirely correct. Retirement Savings Contributions Credit $ 845 A married couple filing jointly with modified AGI of $37,500 and an IRA contribution of $1,690. a. $ 168 b. A married couple filing jointly with modified AGI of $58,000 and an IRA contribution of $1,680. $ 188 C. A head of household taxpayer with modified AGI of $33,000 and Roth IRA contribution of $1,880. $ 1.263 d. A single taxpayer with modified AGI of $12,000 and an IRA contribution of $2,525