Glycolysis and gluconeogenesis are reciprocally regulated at the steps that interconvert fructose-6-phosphate and fructose-1,6-bisphosphate. Which of the following statements about this regulation is TRUE? a) Fructose-2,6-bisphosphate inhibits phosphofructokinase-1 (PFK-1). b) Fructose-2,6-bisphosphate is produced from fructose-1,6-bisphosphate. c) The production of fructose-2,6-bisphosphate increases in response to glucagon. d) Phosphofructokinase-2 (PFK-2) is activated by protein dephosphorylation.