What is the best way for a manager to deal with a situation in which a guest receives a food item that contains peanuts even after she communicated her peanut allergy in advance?

A.
not to tell the guest anything
B.
to send the server who made the mistake to apologize to the guest
C.
to immediately apologize to the guest and call for medical attention
D.
to give the guest a complimentary dessert
E.
deny that the guest mentioned an allergy to peanuts