Which of the following statements about insulin is correct?
- AInsulin is produced by the liver when the blood glucose concentration is high. Its target cells are in the pancreas.
- BInsulin is produced by the liver when the blood glucose concentration is low. Its target cells are in the pancreas.
- CInsulin is produced by the pancreas when the blood glucose concentration is high. Its target cells are in the liver.
- DInsulin is produced by the pancreas when the blood glucose concentration is low. Its target cells are in the liver.