Hi there!
Interesting question about cellular respiration & photosynthesis.
Glycolysis is the first step when it comes to breaking down glucose (6 carbon) into pyruvic acid (3 carbon). Glycolysis occurs in the cytoplasm. On the other hand, the Krebs cycle, which I like to call the tricarboxylic cycle, is a group of chemical reactions that take Oxygen (O2) and turn it into Carbon dioxide (CO2) and water (H2O) as waste products. The Krebs cycle occurs in the mitochondria.
Therefore, your answer should be A. cytoplasm, mitochondria.
