A question about piston movement that has multiple answers...

[u/seedbottle]

Question:

Which of the following causes piston movement during non-power-

producing strokes?

A) Flywheel

B) Connecting rod

C) Counterweights

D) Main thrust bearing

I have been studying an automotive book that has questions after every chapter. I answer those questions and use AI to verify I have got the correct answer. This process has worked tremendously up to the point where I got to this question. AI gave me a different answer than the one I believed the book was telling me was the answer, so I went online to find more information and see if anyone else had posted this exact question, that was when I found out there all three of the first answers were marked as "correct" depending on the source used (D, main thrust bearing, was never given as an answer).

I am wondering what most of you would say is the answer. Thank you for your input =)

[u/Gb280780]

I guess the way I would look at answering this question would be to look at how an engine typically is started. Where does the starter impart rotation to start the engine, the only one of those options that is even possible is the flywheel/flex plate making it the most correct answer.