HMS, BM EQ-Bank 148 MC A marathon runner hits "the wall" after 30 kilometres of running. Which fuel source has most likely been depleted? Creatine phosphate Blood glucose Muscle glycogen Plasma proteins Show Answers Only \(C\) Show Worked Solution C is correct: Muscle glycogen depletion occurs in prolonged exercise Other Options: A is incorrect: CP depletion occurs in seconds B is incorrect: Blood glucose is maintained through liver glycogen D is incorrect: Proteins are not a primary fuel source