A $55$ year$-$old supervisor at a private company, who has always received good performance appraisals, is nevertheless fired. Two younger supervisors $(37$ and $42$ years old, respectively$)$ from the same department and whose performance appraisals have been lower than the $55$ year old's, were nonetheless retained by the company. The employer says that it had to save money and that the older supervisor earned considerably more money than the younger supervisors, which he did. If the termination is legally challenged, a court would most likely decide