Which of the following is the principle that a magnetic speed sensor/pickup operates on?

Correct Answer: Option A — Voltage is produced when a ferrous material moves through a magnetic field.

Magnetic speed sensors operate on the principle of electromagnetic induction. As the ferrous teeth of a target wheel pass the sensor's pole piece, they disrupt the magnetic flux field. This change in flux induces an alternating voltage in the sensor's coil, which is then processed to determine rotational speed.