The correct option is D Solanaceae
A flower when cut in two equal halves through any vertical plane passing through the axis then its symmetry remains undisturbed. Such flower is called as an actinomorphic flower.
Cannaceae flowers are asymmetric which cannot be cut into two equal halves when cut through any vertical plane.
Poaceae and Papilionaceae flowers are zygomorphic as their symmetry remains intact when the flower is cut into two equal halves only through one particular vertical plane passing through the center.
Solanaceae flowers are actinomorphic.
Thus, the correct answer is option D.