Determine the maximum contribution that can be made to a Keogh plan in each of the following cases. In all instances, the individual is self-employed, and the self-employment tax reduction has already been taken. a. Self-employment income of $51,000 b. Self-employment income of $51,000 and wage income of $32,500 C. Self-employment income of $130,000. d. Self-employment income of $285,000. a. Maximum keogh plan contribution b. Maximum Keogh plan contribution C. Maximum Keogh plan contribution d. Maximum Keogh plan contribution