JD, age 26, is a self-employed plumber. One month ago, he hired his brother, age 20, to help in the business. JD wants to accumulate a retirement fund and decides to adopt a 401(k) plan to fund his retirement. JDs net earnings (after certain adjustments) are $80,000.

What is the maximum tax-deductible contribution JD can make to the 401(k) plan?

Does JD have to include his brother in his 401(k) plan? Explain your answer.