Which is correct?(10 POINTS + .... FOR CORRECT ANSWER)?

I saying C becuase there is twice as many Cl atomes per liter of solution and the Zn has got to have .40M, but isn't Cl diatomic so it should ionize at the same ratio as the zinc. . . I don't maybe someone else can help u. If i had to pick i would go with C. Also i don't even think ZnCl is soluble in water. I don't have a chart to go off of here, so i leave that up to u.