For which from the given equilibriums an increase of pressure does not exert influence on the displacement of an equilibrium: a) 2HBr (g) H2 (g) + Br2 (g); b) СО2 (g) + Н2 (g) Н2O (g) + СО (g) ; c) N2O4 (g) 2NO2 (g) ; d) 2CO (g) + O2 (g) 2CO2 (g) ; e) N2 (g) + O2 (g) 2NO (g)