The correct option is C It may or may not be whole number.
Molecularity is a theoretical concept, and can’t be found experimental.
The molecularity of a reaction is defined as the number of molecules or ions that participate in the rate determining step.
Molecularity have to be only natural numbers because molecularity is defined as no. of reactant molecules colliding with each other simultaneously in an elementary reaction.
So molecularity can’t be negative, fractional zero.