Did Sam Give Valid Consent for Officer Thompson to Go

Did Sam give valid consent for Officer Thompson to go into the kitchen

A) Yes, Officer Thompson has apparent authority to search because Sam nodded agreement.
B) Yes, Officer Thompson asked for consent without using coercion.
C) No, Officer Thompson must advise Sam of his Fourth Amendment rights before he can obtain consent.
D) No, Sam does not have apparent authority to give consent to a search of the kitchen.