What Is a Distinct Advantage of External Electronic Fetal Monitoring

What is a distinct advantage of external electronic fetal monitoring (EFM) ?

A) The ultrasound transducer can accurately measure short-term variability and beat-to-beat changes in the fetal heart rate (FHR) .
B) The toco transducer can measure and record the frequency,regularity,intensity,and approximate duration of uterine contractions.
C) The toco transducer is especially valuable for measuring uterine activity during the first stage of labor.
D) Once correctly applied by the nurse,the transducer need not be repositioned even when the woman changes positions.