Who Is Demonstrating a Typical Pattern of Tolerance to Tobacco

Who is demonstrating a typical pattern of tolerance to tobacco?

A) Miriam: her heart is racing when she first wakes up and does not slow down until she has her first cigarette.
B) Craig: smoking has no effect on his heart rate until it abruptly speeds up at the end of the day.
C) Sarah: after her first cigarette in the morning, her heart races; as the day goes on, her cigarette smoking has less of an effect on her heart rate.
D) John: his heart rate gradually increases throughout the day as he increases his cigarette intake.