What is the maximum IRA contribution that Mr. Janson can make under each of the following assumptions? a. He is age 20 and single. His only income item is $13,300 interest from a trust fund. b. He is age 40 and single. His only income item is a $39,000 share of ordinary income from a partnership. c. He is age 60 and single. His only income item is $20,800 wages from his job. d. He is age 46 and files a joint return with his wife. His sole proprietorship generates a $7,080 loss, and his wife's salary is $42,700. a Maximum contribution $ 0 b Maximum contribution Maximum contribution Macimum contribution d