Series of reactions in which CO2 is converted into glucose in the stroma.
A) Glysolysis.
B) Krebs cycle (citric acid cycle).
C) Calvin cycle (light-independent reactions of photosynthesis).
D) Light-dependent reactions of photosynthesis.
E) Chemiosmosis: Process in which sugar is oxidized to pyruvic acid.

Explanation:

1.The Calvin cycle is a dark reaction because it does not require sunlight. Although it can also occur during the day time.

2. Calvin cycle also known as Calvin-Benson cycle, light-independent reaction, carbon fixation and C3 pathway.

3. In this reaction, CO₂ is fixed  into sugar by enzyme RUBISCO.

4 The Calvin cycle completed in three steps : i) carbon fixation, ii) reduction, and iii) regeneration.  

5. This process occurs in the stroma of chloroplast..

i believe the answer would be b. hope it : )