The letter A (option B) represents the stroma in which Calvin cycle or dark reactions of photosynthesis.
What is stroma?
The fluid-filled interior area of the chloroplasts that surround the grana and thylakoids is known as the stroma.
What is contained in the stroma?
Along with the ribosomes, starch, and chloroplast DNA, stroma also has the Calvin cycle-related enzymes.
What does letter B indicate?
The letter B indicates the space between the two membranes of chloroplast known as the intermembrane space.
What does letter C indicate?
Letter C indicates the thylakoid that are disc shaped membrane bound compartment in the chloroplast.
What does letter D indicate?
Letter D indicates a granum which is a stack of thylakoid.
To learn more about stroma, dark reactions, and chloroplasts here,
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