In one study, participants were injected with the hormone adrenaline. When asked how they felt, the participants simply reported the physical changes produced by the drug, saying, "My heart is beating very fast." Some reported feeling "as if" they should be feeling an emotion, but they said they did not feel the emotion itself: "I feel as if I were afraid." These results conflict with the theory of emotion. Select one: a. Ekman b. Cannon c. Two-factor d. James–Lange