Determine whether each of the following taxpayers must file a return in 2016:
a. Jamie is a dependent who has wages of $4,050.
b. Joel is a dependent who has interest income of $1,200.
c. Martin is self-employed. His gross business receipts are $24,050, and business expenses are $24,300. His only other income is $2,600 in dividends from stock he owns.
d. Valerie is 68 and unmarried. Her income consists of $6,500 in Social Security benefits and $11,500 from a qualified employer-provided pension plan.
e. Raul and Yvonne are married and have 2 dependent children. Their only income is Raul's $21,000 salary.