Which of the following individuals are required to file a 2014 Federal income tax return? Should any of these individuals file a return even if filing is not required? Why or why not?

a. Patricia, age 19, is a self-employed single individual with gross income of $5,200 from an unincorporated business. Business expenses amounted to $4,900.
b. Mike is single and is 67 years old. His gross income from wages was $10,800.
c. Ronald is a dependent child under age 19 who received $6,500 in wages from a parttime job.
d. Sam is married and files a joint return with his spouse, Lana. Both Sam and Lana are 67 years old. Their combined gross income was $22,750.
e. Quinn, age 20, is a full-time college student who is claimed as a dependent by his parents. Quinn reports taxable interest and dividends of $2,500.