Answer: the employer's defense was a pretext.
Step-by-step explanation:
Norm providing evidences that him being fired was unfair shows that Norm is attempting to show that the employer's defense was a pretext.
A pretext simply refers to a false reason which covers the true intentions or motives of an employer. In this case, the employer didn't fire Norm because he didn't meet his sales quota but fired him because of his age.
Therefore, all the defense given by the employer shows that his defense was a pretext.