Why Doesn't Blood Typing Definitively Determine If a Particular Man

Why doesn't blood typing definitively determine if a particular man fathered a particular child?

A) Blood typing doesn't tell you anything about the genetics of the father or child.
B) Blood typing can only tell you if a man couldn't have been the father, not if he is.
C) It's difficult to determine the blood type of a child.
D) Because all blood types are unique, there's no way to compare them.
E) Our blood type comes only from our mother.