35. When a client exercises at 65% of VO2 max for 90 min, what is the typical response of the R (respiratory exchange ratio) value, and what does this response mean?
O a. It typically drifts upward, indicating a greater reliance on carbohydrate for fuel.
O b. It typically drifts upward, indicating a greater reliance on fat for fuel.
O c. It typically drifts downward, indicating a greater reliance on carbohydrate for fuel.
O d. It typically drifts downward, indicating a greater reliance on fat for fuel.