For the reaction A ? B, ?G = -60 kJ/mol. The reaction is started with 10 mmol of A. no B is initially present. After 24 hours, analysis reveals the presence of 0.2 mmol of B, 9.8 mmol of A. Which is the most likely explanation? a. A and B have reached equilibrium concentrations. b. Formation of B is thermodynamically unfavorable. c. The result described is impossible, given the fact that delta G is -60 kJ/mol. d. The activation energy for the reaction is very large; equilibrium has not been reached by 24 hours. e. An enzyme has shifted the equilibrium toward A.