Patient with blood type AB RH+ can receive any type of blood, but patient with blood type AB RH- can receive all type of blood which also have RH- factor.
So here if we don't know the RH factor then the safest option is to give this patient AB RH-.
But if we would know that patient have RH+ factor then he can receive any blood type no matter what is the RH factor or blood type.
So correct answer is D. AB RH-
