A, B, and O blood type in humans is controlled by a single gene with three alleles: A, B, O.?

Krish the fish is right on all but question #1. The ONLY correct answer for 1 is B, and here's why: answer E states that both parents MUST be oo. An Ao and an oo, or a Bo and oo are not allowed under this premise, yet both have a 25% chance of producing o offspring.