If the uncatalyzed reaction occurs in a single elementary step, why is it a slow reaction?

The choices can be found elsewhere and as follows:

A) The reaction requires the collision of three particles with the correct energy and orientation.

B) All reactions that occur in one step are slow.

C) The probability of an effective three-particle collision is low.

D) The transition state is low in energy.

I think the correct answer from the choices listed above is option C. If the uncatalyzed reaction occurs in a single elementary step, it is a slow reaction because the probability of an effective three-particle collision is low.