To solve this problem, we need to determine the possible genotypes of the parents and child based on the ABO blood group system.$\newline$Given:$\newline \bullet$Father's blood group: B⁺$\newline \bullet$Mother's blood group: A⁺$\newline \bullet$Child's blood group: O⁺$\newline$The possible genotypes for each blood group are:$\newline \bullet$Blood group A: IᴬIᴬ or Iᴬi$\newline \bullet$Blood group B: IᴮIᴮ or Iᴮi$\newline \bullet$Blood group O: ii$\newline$For the child to have blood group O (genotype ii), both parents must contribute an i allele.$\newline$Therefore, the possible genotypes for the parents are:$\newline \bullet$Father (B⁺): Iᴮi (since he must contribute an i allele)$\newline \bullet$Mother (A⁺): Iᴬi (since she must contribute an i allele)$\newline$Now, let's analyze the options:$\newline \bullet$Option A: IᴮIᴮ / Iᴬi / ii$\newline$ - Father: IᴮIᴮ (cannot contribute an i allele, so incorrect)$\newline \bullet$Option B: IᴮIᴮ / IᴬIᴬ / ii$\newline$ - Father: IᴮIᴮ and Mother: IᴬIᴬ (neither can contribute an i allele, so incorrect)$\newline \bullet$Option C: IᴬIᴮ / iiA / Iᴮi$\newline$ - Incorrect format and does not match the given blood groups$\newline \bullet$Option D: Iᴬi / Iᴮi / Iᴬi$\newline$ - Incorrect format and does not match the given blood groups$\newline \bullet$Option E: iIᴮ / iIᴬ / IᴬIᴮ$\newline$ - Incorrect format and does not match the given blood groups$\newline$The only correct option that matches the requirement for the child to have blood group O is:$\newline$Option 3: A only