please help and explain

The equilibrium constant, Kc, for the reaction H2(g)+I2(g)2HI(g) is 55 at 425C. The value for the equilibrium constant will be changed if A. concentrations are given in atmospheres instead of mol/L. B. a catalyst is added to the reaction system. C. the size of a reaction vessel is doubled. D. the temperature is changed to 400C. E. additional HI is added to the reaction system a catalyst is added to the reaction system. the size of the reaction vessel is doubled. additional Hl is added to the reaction vessel. the temperature is changed to 400C