An individual who has been treated for type 2 diabetes for the past 24 years had, as part of his annual physical, a 24-hour urine collection. Reduced levels of creatinine were found, which is most likely because of which one of the following?
A decreased dietary intake of creatine A higher-than-normal muscle mass resulting from weightlifting A genetic defect in the enzyme that converts creatine phosphate to creatinine Kidney failure