A researcher was measuring how long patients in a cardiac rehab program could walk on a treadmill before they became short of breath. The length of time was measured in minutes for each subject, but for those subjects who were fine after 30 minutes, the researcher stopped the treadmill and recorded "over 30 minutes" for their time. The best measure of central tendency to use for this study is: Question 37 options: a. the mode b. the median c. the mean d. the standard deviation