Mrs. Bland is type “A” and Mr. Bland is type “O.” They have three children named Tony, Toni, and Tone. Toni is type “O,” Tony is type “A,” and Tone is type “AB.” Based on this information:
a. Mr. Bland must have the genotype ______
b. Mrs. Bland must have the genotype ______ because ___________ has blood type ______
c. Tone cannot be the child of these parents because neither parent has the allele _____.