The Reaction a + 3B $\rarr$ D + F Was Studied, and the Following Mechanism Was

The reaction A + 3B $\rarr$ D + F was studied, and the following mechanism was determined The step with largest activation energy is

A) the first step.
B) the second step.
C) the third step.
D) None of the steps has an activation energy.
E) All of the steps have the same activation energy.