In 2023, Megan's sole proprietorship earns $300,000 of self-employment net income (after the deduction for one-half of self-employment tax). a. Calculate the maximum amount that Megan can deduct for contributions to a defined contribution Keogh plan: b. Suppose Megan contributes more than the allowable amount to the Keogh plan. What are the consequences to her? Contributions in excess of the allowable amount under 415 be subject to a I deductible, and they may % excise tax. c. Can Megan retire and begin receiving Keogh payments at age 58 without incurring a penalty? because Megan may not begin receiving payments until age without incurring a penalty.