The correct option is B Thylakoid membranes
The main role of chloroplasts is to conduct photosynthesis.
All chloroplasts have at least three membrane systems—the outer chloroplast membrane, the inner chloroplast membrane, and the thylakoid system.
Embedded in the thylakoid membranes are important protein complexes (that contain the photosynthetic pigments) which carry out the light reactions of photosynthesis.