Which of the Following Meets the Definition of Competitive Employment

Which of the following meets the definition of competitive employment?

A) Ariel fills stockings in a sheltered workshop. She earns $.50 for each one she fills.
B) Brad stocks shelves at a local grocery store without assistance. He earns $3 an hour.
C) Sarah wipes and clears tables at a local restaurant without supervision. She earns minimum wage.
D) Tanya provides day care during a library program and no longer needs supervision but works to gain experience rather than money.