i, iii and iv
iii only
ii, iii and i
iv only
Correct answer is D
i, ii will have no effect because the number of mole of reactants(volume) is equal to the number of mole of the product(volume) and iii will also have no effect since the forward reaction which favours the production of hydrogen is exothermic, therefore, the production of hydrogen will be favored by iv only.