Respuesta :

i think its gonna be c collide

Reactant molecules collides when they create chemical reactions

Explanation:

In a chemical reaction, there is the chemical transformation of chemical substances. There are changes in positions of electrons. Either there will be a  formation of  bonds between atoms or breaking of bonds between atoms.  

To initiate a chemical reaction, molecules must collide with required amount of  energy to break the chemical bonds. With the rise in temperature, molecules move with high speed and vigorously. It increases the likelihood of bond breakage on collision.