B. Chef B is correct.
Carryover cooking is when food retains heat and continues to cook even after being removed from the source of heat. It is a popular method among chefs to let meat rest for some time after it is taken off from the heat, this is done mostly for roasted and grilled foods such as meat, it helps the heat on the surface to penetrate deeper into the center of the meat, and this helps to enhance tenderness, increase flavor and also makes meat juicier.