Which of these converts the reciprocating motion of the piston into rotary motion?

The right approach is "Crankshaft".

Explanation:

Using the composite material gets converted this same reciprocating motion of such a piston to rotary motion. The connecting rod seems to be the intermediary between some of the piston and perhaps the crankshaft. Whenever the piston would be reciprocated from TDC instead to BDC, perhaps the crankshaft moves clockwise somewhere throughout the primary wheels Piston would be directly linked to the connecting rod to that same gudgeon pin as well as the crankshaft has been associated with the connecting rod to something like the crank.

The answer is rom or read only storage devices