What Is an Advantage of External Electronic Fetal Monitoring

What is an advantage of external electronic fetal monitoring?

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