If a reaction involves gases and the pressure is increased, how will the equilibrium change?
a. towards the reactants.
b. towards the side with the fewest molecules.
c. towards the side with the most molecules.
d. towards the products.

The answer to your question is: B Towards the side with fewest molecules

Explanation:

If the pressure is increased, the equilibrium changes to:

A. Towards the reactants.  This option is incorect because it must be consider the amount of molecules in reactants and products.

B. Towards the side with the fewest molecules.  This option in correct, if the pressure increses in order to disminishes pressure it shift towards there are less molecules.

C. Towards the side with the most molecules.  If  the equilibrium would shift to the side with most molecules, the pressure increase even more.

D. Towards the products. It must be consider the amount of molecules in the reaction.