Trevor, the triathlete, is looking over the chart and following the line that shows what happens to blood glucose if no carbohydrates are consumed during exercise. He laughs and says, "Been there, done that. I didn't finish the race." His question to you is why consuming carbohydrates during a triathlon helps. How would you explain the effect? a. The carbohydrates provide glucose directly to the blood. b. The carbohydrates spare muscle glycogen. c. The carbohydrates spare liver glycogen. d. All of the above are true.