You are conducting a study to investigate the phenomenon known as "blocking." Consequently, you will:___
a. first present the CS prior to the US; then, once the CR is established, present the US prior to the CS.
b. first present the CS prior to the US; then, once the CR is established, present the CS prior to a sec and US.
c. first present the CS prior to the US; then, once the CR is established, present the original CS simultaneously with a second CS prior to the US.
d. first present the CS prior to the US; then, once the CR is established, present a second CS prior to the original CS.