Correct option is D
Scavenging is the process of clearing out (or “flushing”) exhaust gases from the cylinder after the combustion process and replacing them with fresh air (or air-fuel mixture in some engines) for the next cycle. This is a critical phase in engine operation, ensuring that the combustion chamber is properly prepared for the next power stroke and that no leftover exhaust gases remain to dilute the incoming charge, which could reduce efficiency and performance.
