Which of the following is necessary for collisions to be successful?
a. enough kinetic energy and favorable geometry
b. enough kinetic energy only
c. sufficient potential energy only
d. favorable geometry only

A. enough kinetic energy and favorable geometry

Explanation: According to collision theory, the rate of a reaction depends upon the number of effective collisions which means the collisions which result in the formation of product which in turn depend on following two factors:-

a) Energy factor: In order for a collision to be successful, the colliding molecules must cross a energy barrier which is called as threshold energy. Thus molecules with energy less than threshold energy are not able to result into products.

b) Orientation factor: the colliding molecules must have proper orientations at the time of collision otherwise they do not result in product formation.