There is double fixation of `CO_(2)` both in `C_(4)` and CAM plants. Which of the following statements brings out the main difference between the two ?
A. Carboxylising enzymes are different
B. Fixation pathways are different
C. `CO_(2)` fixation in `C_(4)` plants is separated by space whereas in CAM plants, it is separated by time
D. The compensation point are different
