Assume that blue flower of a plant is dominant character over white. When a blue flowered plant is crossed with white flowered plant, the progeny showed 50% of plants with blue flowers and 50% of plants with white flowers. The genotypes of blue and white parents respectively are

$\begin {array} {1 1} (1)\;Bb, \: bb & \quad (2)\;bb,\: bb \\ (3)\;BB,\: Bb & \quad (4)\;BB,\: bb \end {array}$

(1) Bb, bb