Think of the combine as a single production line the crop passes through in one direction, from standing in the field to clean grain in the tank.
First the reel reaches out and gathers the standing stalks, holding them steady. Next the cutter bar slices through the stems at the base. The severed crop then slides onto the moving platform, where the auger gathers it toward the center and pushes it into the feeder house. Inside the machine, the cylinder spins against the concave, rubbing and impacting the crop heads to knock the grain loose. What remains, mostly straw with some trapped grain, moves onto the straw walkers, which shake it so the last bits of grain fall through to the cleaning shoe while the spent straw exits the rear.
This gives the sequence Reel, Cutter bar, Auger, Cylinder and concave, Straw walker.
\[\boxed{\text{(E), (A), (B), (D), (C)}}\]