The information shows the masses after the compounds are balanced. 2MgO + 2Cl2 → 2MgCl2 + O2

85g + 156g → 188g + ?

If the following materials are used during the reaction of magnesium, oxygen, and chlorine, what mass oxygen would we expect to see after the reaction and why?

A. 53g of O2, because all mass must be conserved.

B. 241g of O2, because all mass must be conserved.

C. 42.5g of O2, because all mass must be conserved, it would be half of the compound MgO in the products.

D. 106g of O2, because all mass must be conserved, it would be double the compound MgO in the products.
Pls answer correctly I really need a good grade on this.