Consider This Reaction at Equilibrium at a Total Pressure P₁

Consider this reaction at equilibrium at a total pressure P₁: 2SO₂(g) + O₂(g) ⇌ 2SO₃(g)
Suppose the volume of this system is compressed to one-half its initial volume and then equilibrium is reestablished. The new equilibrium total pressure will be

A) twice P₁.
B) three times P₁.
C) 3.5 P₁.
D) less than twice P₁.
E) unchanged.