Enzymes Work by ___________ $\Delta$ G of a Reaction and Thus Speeding Up the Reaction

Enzymes work by ___________.

A) raising the activation energy of a reaction and thus speeding up the reaction.
B) lowering the activation energy of a reaction and thus speeding up the reaction.
C) raising the $\Delta$ G of a reaction and thus speeding up the reaction.
D) lowering the $\Delta$ G of a reaction and thus speeding up the reaction.
E) changing the free energy of the products and speeding up the reaction.