The correct option is C stroma
Photosynthesis is a unique process during which the plants utilise relatively simple substances like CO2, water and synthesise food in presence of sunlight and chlorophyll. The site of photosynthesis is the green plastid, chloroplast. Chloroplast is a double membrane bound cell organelle having an inner and outer membrane.
Photosynthesis includes light dependent reaction and light independent reaction.
Light independent reaction of photosynthesis does not require light. It takes place in the matrix of chloroplast, stroma. The stroma has all enzymes required for the light independent reactions. The detailed reactions occurring in stroma were worked upon by Calvin and his colleagues. The carbon dioxide fixation occurs during these reactions and there is synthesis of sugar.
The light dependent reaction takes place in the grana. Grana are made up of units called thylakoids. The thylakoid membrane has pigments to trap light energy and carry out light dependent reactions.
Inner membrane of chloroplast does not have any obvious function during light reaction.