If the husband blood group is A+ and the wife is O+, what is the possible blood group of their children?

Question

If the husband blood group is A+ and the wife is O+, what is the possible blood group of their children?

Answer 1

50% of -o 25% of 0+ a % 25

Answer 2

A+, A-, O-, O+

Answer 3

Well, according to this blood type calculator, the children could be A or O  and + or -

http://www.biology.arizona.edu/Human_Bio...