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 $64,000. b. Self-employment income of $64,000 and wage income of $39,000. c. Self-employment income of $195,000. d. Self-employment income of $298,000.