9. The general structure of the porphyrin molecule is shown on the right side. This molecule is planar and so we can approximate the π electrons as being confined in a square with the length a = 10
The porphyrin molecule has "22"π electrons. According to the particle in a two-dimensional (2D) box, the energy states are given by

where nx and ny are quantum numbers. Assume that each energy levet in the box is capable of holding no more than two electrons. What is the electronic transition responsible for the promotion of an electron from the highest filled energy level to the lowest empty energy level? (A) E(3,3)→E(4,2) (B)E(3,2)→E(4,1) (C) E(2,3) → E(2,4) (D) E(3,3)→E(4,3) (E) E(3,4) → E(4,4)