Technician A says that the crankshaft determines the stroke of an engine. Technician B says that the length of the connecting rod determines the stroke of an engine. Which technician is correct

Technician A is correct.

Explanation:

Stroke of the engine means how far is the piston moves during the cycle.It is determined by the crank of the crank shaft. Engine displacement volume  is calculated by multiplying length of the stroke to the piston displacement area.

                          If there are more than one cylinder in the engine, than in that case this number in multiplied by the number of the cylinders inside the engine.

Therefore technician A is correct.