Which method is used to calculate a patient's regular heart rate on a regular EKG rhythm? a) Counting the number of QRS complexes in a 6-second strip and multiplying by 10. b) Counting the number of P waves in a 10-second strip and multiplying by 6. c) Measuring the distance between the R waves and converting to heart rate. d) Counting the number of T waves in a 12-lead EKG and multiplying by 5.