Genotype of the Offspring

Irene’s daughter is type A and her grandson’s is type B+. She does not know the type of either father. She wants to know the possible blood types of the fathers in order for her grandson to be a B+?

(a) B or O
(b) A, B, AB or O
(c) AB or B
(d) A or B
(e) A, B, or AB