Final answer:
In Photosystem II, the incoming photon has higher energy than the energy required for the primary excited state to allow for energy losses through nonradiative decay as heat before being passed to the primary electron acceptor.
Step-by-step explanation:
In Photosystem II, the energy discrepancy between the incoming photon and the energy required for the primary excited state is addressed through a process known as fluorescence. As incoming photons excite electrons in the chlorophyll molecules to a higher energy state, some energy is inevitably lost through nonradiative decay as heat.
Therefore, when we consider the energy of the emission wave (the energy emitted when the electron returns to the ground state), it is lower than that of the incoming excitation photon, due to this energy loss.
The chlorophyll molecules, including chlorophyll a, become excited upon absorption of light and they pass this energy to the primary electron acceptor. The incoming photon thus must have higher energy than the energy required for the primary excited state to accommodate for this energy loss in the form of heat and still be able to drive the electrons through the photosynthetic electron transport chain.
Therefore answer is a. The incoming photon has higher energy.