Answer: increases.
You can infere that from the fact that the pressure is proportional the the concentration, which in turn you can deduce from the ideal gas law:
pV = nRT
=> p = nRT / V = (n/V) RT
Where n/V is the concentration. So, you got that at constant T, p is proportional to the number concentration, which leads you to the conclusion that if the pressure exerted on a gas increases, the reaction rate increases.
