Answer:
B. All males could be the father
Explanation:
A woman with type A blood either has the genotype AA or Ai. A child with type A blood will also either have AA or Ai.
Type B blood is BB or Bi. Type AB blood is AB. Type O is ii.
To find out the men not be the father, you have to do Punnett squares between the mother and father.
AA mother with BB father - type AB child
AA mother with Bi father - type AB and type A child
Ai mother with BB father - type AB and type B child
Ai mother with Bi father - type AB, type B, type A, and type O child
AA mother with AA father - type A child
AA mother with Ai father - type A child
Ai mother with AA father - type A child
Ai mother with Ai father - type A and type O child
AA mother with AB father - type AB and type A child
Ai mother with AB father - type AB, type A, and type B child
According to these crosses, all males could be the father. The father with type B blood must have the genotype Bi. The father with type A blood can have either genotype AA or Ai. The father with type AB blood will always produce a type A child except with a woman who has the genotype BB for type B blood.
Hope that helps.
