To Determine the Extent of a Patient's PAD,how Does the Nurse

To determine the extent of a patient's PAD,how does the nurse perform an ankle-brachial index?

A) By subtracting the mean ankle BP from the mean brachial BP
B) By dividing the Doppler ultrasound-obtained ankle systolic BP by the highest brachial systolic BP
C) By comparing the amplitude of blood flow of the brachial artery with that of the posterior tibial artery using a Doppler ultrasonograph
D) By using a Doppler ultrasonograph to take blood pressures at the brachial artery,thigh,and ankle to determine the change in pressures