Which of the Following Statements Is an Example of Operant

Which of the following statements is an example of operant conditioning?

A) conditioning a dog to drool at the sound of a bell by pairing it with food
B) teaching a child to behave by rewarding them when they are good and punishing them when they misbehave
C) conditioning a person to become hungry at the sight of red and yellow by using red and yellow striped food wrappers
D) a person who becomes ill from clams gaining an aversion to them