When aqueous solutions of magnesium chloride and sodium hydroxide are mixed, magnesium hydroxide precipitates out. Suppose that 100.0 mL of a 0.120 M solution of magnesium chloride is mixed with 100.0 mL of .210M sodium hydroxide. Assume that the volumes are additive (which is only approx correct) and calculate the molarity of the chloride ion in the final solution.

A) .0600 M

B) .105 M

C) .120 M

D) .240 M

E) None of these