Which of the following are actual anaplerotic reactions?

a. fumarate + H2O ⇌ malate
b. phosphoenolpyruvate + ADP ⇌ pyruvate + ATP
c. oxaloacetate + acetyl-CoA + H2O ⇌ citrate + CoA-SH
d. phosphoenolpyruvate + CO2 + GDP ⇌ oxaloacetate + GTP
e. pyruvate + HCO3– + NADH ⇌ malate + NAD+