Which change will favour the reverse reaction in the equilibrium?

\[{\text{2CrO}}_{\text{4}}^{2 - }{\text{(aq)}} + {\text{2}}{{\text{H}}^ + }{\text{(aq)}} \rightleftharpoons {\text{C}}{{\text{r}}_{\text{2}}}{\text{O}}_{\text{7}}^{2 - }{\text{(aq)}} + {{\text{H}}_{\text{2}}}{\text{O(l)}}\;\;\;\;\;\Delta H =  - {\text{42 kJ}}\]

A.     Adding \({\text{O}}{{\text{H}}^ - }{\text{(aq)}}\)

B.     Adding \({{\text{H}}^ + }{\text{(aq)}}\)

C.     Increasing the concentration of \({\text{CrO}}_{\text{4}}^{2 - }{\text{(aq)}}\)

D.     Decreasing the temperature of the solution

A