The correct option is A 2
When CO2 is added to water, it forms carbonic acid, H2CO3. So each mole of CO2 gives you two moles of acid. That would make the 44 / 2 = 22 g equivalent.
As per photochemical equation, it suggests that for 1 mol H2O there is 1 mol of CO2,
So, as molar mass of CO2 is 44 g/mol.
So, for 1 mol CO2, the number of equivalents = 44 / 22 = 2 equivalents.