A Particular Flower Can Be Purple, Blue, Red, or White

A particular flower can be purple, blue, red, or white.A pure-breeding red plant is crossed with a pure-breeding white one, and the F₁ are then crossed to produce an F₂ generation.Which of the following phenotypic ratios in the F₂ indicate that flower color in these plants is controlled by two genes?

A) 2:1
B) 3:1
C) 1:2:1
D) 9:3:4