The blood group of a woman is 'O'. She has two brothers ; one with 'A' group and the other with 'B' group. The genotypes of her parents are :

Question

$\begin {array} {1 1} (1)\;I^A\: I^O - I^A\: I^B & \quad (2)\;I^A\: I^O - I^B\: I^O \\ (3)\;I^A\: I^B - I^O\: I^O & \quad (4)\;I^O\: I^O - I^A\: I^O \end {array}$