Answer:
c. they enter an electron transport chain.
Step-by-step explanation:
The chlorophyll in leaves of plants undergoing photosynthesis is made up of two pigments ; these are the primary pigments and the accessory pigments. The latter are arranged around the primary pigments. These two pigments are arranged in chlorophyll to form photo systems i and ii. The photosystems serves as the reaction centers of chloroplast. Basically the accessory pigment absorbs photons of energy and sends this to the primary pigments.
When photons of light is absorbed by the chlorophyll of the leaf. The electrons in the chlorophyll are excited, and therefore move to higher energy levels. At this stage they are said to be activated. This process is called Photoactivation.
However, instead of the excited electrons to return to the photo- systems so that the acquired energy is lost as heat to the surroundings, these electrons are trapped by electron acceptors and are passed to the electron transport chains. These chains of electrons generate proton motive force PMF, for pumping protons across the thylakoid membranes , down into the thylakoid for the synthesis of ATPs by ATPase synthase; through Chemiosmosis.
The ATP is needed in Calvin's Cycle for Carbohydrates synthesis.