Which of the Following Scenarios Exemplifies Extinction

Which of the following scenarios exemplifies extinction?

A) Alexis is a former cocaine user.Now that she no longer uses cocaine,her hands no longer shake and her heart no longer pounds when she hears a car pull into her drive,like her dealer used to do in his car.
B) Alexis uses cocaine.She no longer feels quite the same rush as she did when she first started using.
C) Alexis is a former cocaine user in recovery.After a relapse,though,her hands shake and her heart pounds when she hears a car pull into her drive,like her dealer used to do in his car.
D) Alexis uses cocaine.She finds that she is slowly losing her sense of smell.