Answer:
C. Crystal is getting the respiration rate when she multiplies the number by two, and Justine is getting the radial pulse
when she multiplies the number by two.
Step-by-step explanation:
Respiration rate and pulse (beats per minute) are most frequently measured vital signs since they don't require any special equipment.
Respiration rate is the number of respiration per one minute and pulse is the number of heartbeats per minute.
Since Justine counts beats on Ben's wrist, where the radial artery passes through, this pulse is called radial pulse. That means that options A and B are incorrect.
Respiratory rhythm shows regularity of breathing pattern and not the number of respirations, so option D is also wrong.
Since both of these vitals are measured for 30 seconds, to get the number per minute, we simply multiply the number by two.