Glucose sparing refers to a phenomenon occurring during the

Glucose sparing refers to a phenomenon occurring during the
 a. absorptive phase of metabolism in which recently ingested glucose is saved in the form of glycogen for future use.
  b. postabsorptive phase of metabolism in which glucose ingested earlier is saved in the form of glycogen for use during prolonged fasting.
  c. postabsorptive phase of metabolism in which numerous body tissues release glucose for immediate use by the brain.
  d. postabsorptive phase of metabolism in which numerous body tissues switch to metabolizing alternative, non-glucose energy sources, so that glucose remains available for the brain.