Elwood had to retire early because of a job-related injury. During the current year, he receives $10,800 in Social Security benefits. In addition, he receives $6,400 in cash dividends on stocks that he owns and $7,900 in interest on tax-exempt bonds. Assuming that Elwood is single, what is his gross income if

a. he receives no other income?

b. he also receives $10,800 in unemployment compensation?

c. he sells some land for $79,600 and he paid $44,100 for the land?