Final answer:
Monica will have to pay income taxes on the withdrawn amount as well as a 10% early withdrawal penalty.
Step-by-step explanation:
Monica, age 30, withdrew $25,000 from her company's SIMPLE IRA this year. Since she has been a participant for 18 months, this withdrawal is subject to both income taxes and an early withdrawal penalty. The implications for Monica are that she will have to pay income taxes on the withdrawn amount as well as a 10% early withdrawal penalty. Therefore, option a) is the correct answer.