The accurate statement about the regulation of carbohydrate metabolism in human is
Insulin reduces the blood glucose level, and glucagon increases it.
Both hormones are secreted from islet of Langerhans of pancreas and one act opposite to another.
Glucagon is a hormone that gives signal to the cells of liver and muscles to convert glycogen into glucose and release it into blood so that cell can use energy from it during its need.
Insulin is a hormone that signals the cells either to take glucose from blood for energy or to store it for later use.