This example question asks, "The primary purpose for the Cori Cycle is to:" Alright. "Produce Lactate through the fermentation process." Lactate is something we don't really want to build up within our muscle cells. Okay. So here, this would make sense as a primary purpose for the Cori Cycle: "To provide a metabolite for gluconeogenesis." Alright. So here, the Cori Cycle, its primary focus, primary reason, and function is not to create a metabolite for gluconeogenesis.
Next, we're going to say "Generate glucose for muscle cells to use as an energy source." This is it. We're converting something that is not great for our muscle cells in the form of lactate and shuttling it off from the muscle cells to our liver to be converted into glucose through gluconeogenesis that can then be shuttled towards our muscles for energy. It helps provide an energy source for our muscle cells. So, this is the answer.
Here, "Provide liver with much-needed energy." Here it's just shuttling over the lactate to the liver cells; the liver itself is helping to convert that lactate into something useful in the form of glucose. So here, the best answer would have to be option C.