Thylakoids possess photosynthetic units called
Thylakoid is a sheet-like membrane-bound structure which is the site of the light-dependent photosynthesis reactions within the chloroplasts and cyanobacteria. Photosystems are then functional and structural units of protein complexes involved in photosynthesis.
The electron transport chain is a series of the proteins and organic molecules which are found in the inner membrane of the mitochondria. Photolysis is the chemical process by which molecules are broken down into smaller units through the absorption of light.
The synthesis of ATP in chloroplasts, promoted by light, is termed as photophosphorylation
So the correct option is A.