Final answer:
The bull's genotype is Hh because it can pass on the recessive allele; Cow A and Cow B are hh, being hornless. A calf can be hornless only if it inherits two recessive alleles.
Step-by-step explanation:
The genetics question pertains to Mendelian inheritance, specifically about predicting offspring phenotypes based on the genotypes of the parents. In cattle, Horned (H) is completely dominant over the hornless (h) condition. Given that a horned bull was bred with two hornless cows and produced both horned and hornless calves, we can deduce the genotypes. The bull must be heterozygous (Hh) because he can pass on the allele for hornlessness (h) to his offspring. As both cows are hornless, their genotype must be homozygous recessive (hh). When the bull (Hh) is crossed with Cow A (hh), the calf is horned (Hh), and when crossed with Cow B (hh), the calf is hornless (hh).