Atoms of different elements can form by combining in a whole number?

What is a property of a double replacement reaction

Choose an equation that represents an enzyme-catalyzed reaction. (a) enzyme + substrate → enzyme-substrate complex (b) enzyme + substrate ←−→ enzyme + products (c) enzyme + substrate ←−→ enzyme-substrate complex → enzyme + products (d) enzyme + substrate ←−→ enzyme-substrate complex → enzyme-substrate complex + products

Which scenario is most similar to the type of collision that gas particles have according to kinetic molecular theory