Areaction is shown below.
what can be concluded about this reaction?
a. a homogeneous catalyst is being used in the reaction.
b. a heterogeneous catalyst is being used in the reaction.
c. a catalyst is not being used in this reaction.
d. an enzyme is being used in this reaction.

I think it would be B "A heterogeneous catalyst is being used in the reaction"

This is because MnO2 is a heterogeneous catalyst as it's in a different state than the rest of the reactants and products.
The MnO2 isn't being used as a reactant so it's a catalyst.
MnO2 is not an enzyme

hope that helps