A 4691-G Sample of MgCl₂ Is Dissolved in Enough Water to to Give

A 4.691-g sample of MgCl₂ is dissolved in enough water to give 750. mL of solution. What is the magnesium ion concentration in this solution?

A) 6.25 M
B) 6.57 × 10^{-2 M}
C) 4.38 × 10^{-2 M}
D) 3.29 × 10^{-2 M}
E) 2.19 ×10^{-2 M}