Which of the Following Are Features of the PR Interval

Which of the following are features of the PR interval?
I.It is measured from the beginning of the P wave to the first ventricular deflection.
II.It is measured from the beginning of the P wave to the S wave.
III.The normal PR interval is between 0.12 and 0.20 second.
IV.The PR interval can be shorter for fast heart rates than for slow heart rates.

A) I, II
B) I, III, IV
C) I, II, III, IV
D) II, III