When a Mixture of 3-Phosphoglycerate and 2-Phosphoglycerate Is Incubated at 25

When a mixture of 3-phosphoglycerate and 2-phosphoglycerate is incubated at 25 °C with phosphoglycerate mutase until equilibrium is reached, the final mixture contains six times as much 2-phosphoglycerate as 3-phosphoglycerate. Which statement is MOST nearly correct, when applied to the reaction as written? (R = 8.315 J/mol · K; T = 298 K) 3-phosphoglycerate $\rightarrow$ 2-phosphoglycerate

A) $\Delta$ G'° is -4.44 kJ/mol.
B) $\Delta$ G'° is zero.
C) $\Delta$ G'°is +12.7 kJ/mol.
D) $\Delta$ G'°is incalculably large and positive.
E) $\Delta$ G'° cannot be calculated from the information given.