A two-cycle engine runs at 3600 rpm's. The number of sparks per minute required at the spark plug would be:

In a two-cycle engine, the piston completes one power stroke every revolution of the crankshaft. As a result, the engine produces one spark for every revolution. If the engine is running at 3600 revolutions per minute (rpm), it will require one spark per revolution. Therefore, the number of sparks per minute is equal to the engine speed in rpm, which is 3600. This directly aligns with the operation of two-cycle engines, where every revolution leads to a spark igniting the fuel-air mixture in the combustion chamber.

The choices relating to lower spark counts, like 1200 or 1800, do not account for the fact that each revolution requires a spark. The choice of 7200 also misrepresents the operational dynamics of a two-cycle engine, as it implies two sparks per revolution, which is not standard for this type of engine. Thus, the requirement of 3600 sparks per minute aligns with the fundamental working principle of a two-cycle engine.