Answer
c.
Work Step by Step
Option a. is incorrect. The chloroplast is the site of photosynthesis.
Option b. is incorrect. The nucleus is not the site of any of the reactions of cellular respiration.
Option d. is incorrect. The cytoplasm is the site of glycolysis.
Option c. is correct. The initial step of cellular respiration, glycolysis, takes place in the cytoplasm. The second step of cellular respiration, the Krebs cycle, takes place in the mitochondria.