Which of the Following Studies Describes a Paired Data Design

Multiple Choice

Which of the following studies describes a paired data design?

A) The testosterone levels of male doctors and male college professors are compared
B) 40 students measure their blood pressure twice--first while resting and then again after running in place for 10 minutes.
C) The mean blood pressure of men is compared to the mean blood pressure of women
D) All of choices A, B, and C involve paired data.