Which of These Descriptions Best Characterizes the Cori Cycle

Which of these descriptions best characterizes the Cori cycle?

A) a process in the liver that regenerates glucose from lactate released by muscles
B) a sequence of coordinated muscle contractions of slow-twitch and fast-twitch fibres
C) an exercise machine that allows development of both aerobic and anaerobic capacities
D) a group of enzymatic reactions that accelerate muscle glycogen repletion in trained athletes