Explanation: Pulse-type interference linked to engine speed is typically generated by the high-voltage ignition system, specifically the arc across the spark plug gap. This electrical discharge creates broadband radio frequency interference (RFI) that can be picked up by radio receivers. Installing resistances in series with spark plug wires (or using resistive spark plug wires) helps to dampen the high-frequency oscillations generated by the spark. These resistors absorb some of the energy, reducing the intensity and duration of the RF pulse radiated from the ignition system, thereby lowering the interference heard on the radio. * **B) Using heavy conductors between the starting battery and the starting motor** is related to ensuring sufficient current for engine starting, not reducing RF interference during operation. * **C) Connecting resistances in series with the battery** would undesirably drop the voltage for the entire vehicle electrical system and would not target the high-frequency noise from the ignition. * **D) Grounding the negative side of the battery** is standard automotive practice for completing circuits and provides a stable ground reference; it does not specifically mitigate ignition noise, which is radiated.