Equilibrium is established in the reaction 2 SO₂(g) + O₂(g) ⇌ 2 SO₃(g) at a temperature where K_c = 100. If the number of moles of SO₃(g) in the equilibrium mixture is the same as the number of moles of SO₂(g), 

(a) The number of moles of O₂(g) is also equal to the number of moles of SO₂(g);

(b) The number of moles of O₂(g) is half the number of moles of SO₂;

(c) [O₂] may have any of several values;

(d) [O₂] = 0.010 M.