Location of dark reactions in chloroplast:

Explanation

The correct answer is the stroma of the chloroplast. This is where the Calvin Cycle, or dark reactions, occur. The stroma contains all the enzymes necessary for carbon fixation and sugar synthesis. The inner membrane primarily serves to enclose the stroma and is not involved in the Calvin Cycle. The grana are stacks of thylakoids where light-dependent reactions take place, not the Calvin Cycle. Finally, the thylakoid membranes are involved in the light-dependent reactions, not the dark reactions.