When using the PISA measurement to calculate the ERO for aortic regurgitant jet, which 3 measurements need to be obtained?
a) Vena Contracta, Regurgitant Volume, Heart Rate
b) Radius, Aliasing Velocity, Color Doppler Gain
c) Nyquist Limit, PISA Radius, Deceleration Time
d) PISA Radius, Vena Contracta, Doppler Shift