Which of the following examples best illustrates functional fixedness? A. Adam needs to keep the door open, so he uses his psychology book as a door stop. B. Trey wants to nail a poster up in his room, so he uses his shoe as a hammer. C. Julie lost her earring back, so she throws the earring away instead of using a pencil eraser. D. Morgan uses a wrench as a paper weight while she writes her essay for psychology outdoors.