The first option will be the best answer because it has the best concept of parental control along with working together by monitoring them.
Answer:
The correct answer is - Changing PRF.
Explanation:
Pulsed wave Doppler uses the principle of Doppler effect that objects that move changes the characteristic of sound waves. It is creates images by sending the short and quick pulses of the sound, it helps in the determining the velocity of blood in a exact time and location.
PRF or pulse repetition frequencies, is a Doppler sampling frequency that can affect the acoustic exposure of the scanning. PRF is measured in KHz.
Thus, the correct answer is - changing PRF.
