3. Sue used a chair with wheels to carry a big load of books to her car. She piled the books in the seat of the chair and pushed it to her car. Trina made several trips carrying books by hand, even though she also had a chair with wheels in her office. Trina was most likely experiencing the effects of .

a. functional fixedness

b. an ill-structured problem

c. heuristic thinking

d. divergent thinking