In 1973, Lepper and colleagues conducted an experiment in which children did drawings. Some of the children were promised a reward while others received a surprise reward. The researchers found that the children who received the expected reward for drawing .

Which of these statements describes clinical depression? a. a milder form of depression that usually follows a traumatic event b. a medical condition that may occur due to a chemical imbalance in the brain c. alternate feelings of extreme happiness and extreme sadness