As you drive to school, you hear a random radio-show caller arguing that sun exposure really has not been proven to cause skin cancer and that some research suggests that skin cancer is completely genetic and not related to sun exposure at all. At the time, you think that this is a silly argument and that the caller does not know what she is talking about. However, two months later, you go outside without wearing sunscreen and you find yourself remembering that you had heard something about how the sun actually does not cause skin cancer. In this situation, __________ has influenced your attitude.
a. the sleeper effect
b. the peripheral route to persuasion
c. thought polarization
d. self-validation