Almost all companies utilize some type of year-end performance review for their employees. human resource (hr) at a university's health science center provides guidelines for supervisors rating their subordinates. for example, raters are advised to examine their ratings for a tendency to be either too lenient or too harsh. according to hr, ``if you have this tendency, consider using a normal distribution -- 10% of employees (rated) exemplary, 20% distinguished, 40% competent, 20% marginal, and 10% unacceptable.'' suppose you are rating an employee's performance on a scale of 1 (lowest) to 100 (highest). also, assume the ratings follow a normal distribution with a mean of 50 and a standard deviation of 20.
what is the lowest rating you should give to an ``exemplary'' employee if you follow the university's hr guidelines?
a. 76
b. 85
c. 90
d. 25