If the mother is A positive and the father is O positive what would the child's blood type be?

If the mother is A type blood and the father is O type blood, there are two options that can arise. Either the mother's A-type goes through and the child's also an A-type, or the mother's A-type doesn't go through an the child's an O-type. Because neither parent sport a B-type in their blood, the child cannot possibly have this blood type.