If You Want a Motion Detector Circuit to Respond to Faster

If you want a motion detector circuit to respond to faster object motions, which changes should you make to the circuit?

A) Reduce the distance between the detectors and/or decrease the time delay.
B) Increase the distance between the detectors and/or decrease the time delay.
C) Reduce the distance between the detectors and/or increase the time delay.
D) Increase the distance between the detectors and/or increase the time delay.
E) Reduce the distance between the detectors and/or change which neurotransmitter they release.