Alicia Walker owns a bookstore called "Alicia's Christian Bookstore". It sells only books about Christianity, and novels with a Christian theme.
The bookstore is doing well, and Alicia realizes she needs to add another cashier to ring up sales.
Muhammed, a Muslim, applies for the job but he is not hired because he is not a Christian. (All 30 of Alicia's other employees are Christian.)
Is this illegal? Explain why or why not.