How Do Researchers Know That Infants Can Tell the Difference

How do researchers know that infants can tell the difference between a physically impossible and physically possible event?

A) Infants will stare longer at the possible event than the impossible event.
B) Infants will stare longer at the impossible event than the possible event.
C) Infants will demonstrate object permanence to the possible event, but not to the impossible event.
D) Infants will demonstrate object permanence to the impossible event, but not to the possible event.