The correct answers are the following.
Neural Stimulus: when the clock chimes exactly at five o'clock.
Unconditioned Stimulus: the cutting of onions.
Unconditioned Response: he starts to cry.
Conditioned Stimulus: the alarm of the clock at five o'clock.
Conditioned Response: the crying.
Elmer is so conditioned due to the permanent habits and activities he has. That is why when similar actions occurred, he reacts in the same way. His brain is having an immediate response to the external conditions and Elmer reacts accordingly.