Harun Is a Newly Arrived Legal Immigrant to the United

Harun is a newly arrived legal immigrant to the United States and secures a new job quickly. But he is soon fired from the new job based on a factor related to his race or ethnicity. Which of the following reasons might his new employer have used that is not considered illegal discrimination?

A) The customer base of the business vastly prefers Caucasian employees and the business would suffer with Harun.
B) Harun's English skills are not good enough to perform the job required.
C) Harun's country of national origin has been placed on a terrorist watch list by the United States.
D) Other employees have shown a strong dislike for Harun, to a degree that is affecting the business.