Which is one of the four strokes in an internal combustion engine?

• A. Power stroke
• B. Exhaust stroke
• C. Intake stroke
• D. Compression stroke

Answer: (C)

In a four-stroke internal combustion engine, the cycle goes through four distinct strokes: intake, compression, power, and exhaust. The one that pulls the air-fuel mixture into the cylinder is the intake stroke. As the piston moves downward with the intake valve open, the volume inside the cylinder increases and a vacuum forms, drawing in air (and fuel in most engines) from the intake manifold. This sets up the next steps where the mixture is compressed, ignited to produce power, and then the spent gases are pushed out during the exhaust stroke. The other options correspond to the remaining strokes: compression makes the mixture denser for a more powerful burn, power is the explosion that drives the piston downward, and exhaust ejects the burnt gases.