The Exergonic Reaction 1,3-Diphosphoglycerate $\rightarrow$ 3-Phosphoglycerate Is Coupled to the Reaction ADP + P_i

The exergonic reaction 1,3-diphosphoglycerate $\rightarrow$ 3-phosphoglycerate is coupled to the reaction ADP + P_i $\rightarrow$ ATP.Which of the following is most likely to be true about the reaction ADP + P_i $\rightarrow$ ATP?

A) The reaction never reaches equilibrium.
B) The reaction is spontaneous.
C) There is a large decrease in free energy.
D) The reaction is endergonic.
E) Temperature will not affect the rate constant of the reaction.