The given information is not sufficient to tell which of the traits, i.e., blood group B or O is dominant. But generally, blood group O is recessive in nature.

Here fathers blood group is B that means it can be either BB (homozygous) or BO (heterozygous) genotypically. Similarly, mother can have genes combination OO or OB. The daughter having blood group O will have received O type gene from each parent. The genes IO and IO combined to give blood group O. For this the father must be heterozygous (BO), and mother must be homozygous (OO). Recessive traits appear when both the parents contribute recessive genes.