对于下列反应，在定温下，增加总压力，平衡常数Kx不变的是
A HCl(aq) + CaCO3(s) = CO2(g) + H2O(l) + CaCl2(aq)
B CaCO3(s) = CaO(s) + CO2(g)
C C(s) + O2(g) = CO2(g)
D N2(g) + 3H2(g) = 2NH3(g)
E H2(g) + Cl2(g) = 2HCl(g)