During physical exercise, a large amount of oxygen is delivered to the active muscles by many physiological adjustments including a change in the P50 value (which is determined by PO2 at which hemoglobin is half-saturated with oxygen). The following proposed statements explain the mechanism of change in P50 during exercise:
A. P50 is increased during exercise as the temperature rises in active muscles.
B. During exercise, metabolites accumulate in the active muscles resulting in higher pH that increases P50.
C. P50 is increased during exercise as CO2 is decreased in active muscles.
D. An increase in 2,3-DPG has been reported in non-trained person within 60 min of exercise resulting in higher P50.
Which one of the following options represents the correct combination of the above statements?