Magnesium is a valuable, light weight metal used as a structural material as well as in alloys, batteries, and in chemical synthesis. Although magnesium is plentiful in Earth's crust, it is mainly found in the sea water (after sodium). There is about 1.3 g of magnesium in every kilogram of sea water. The process for obtaining magnesium from sea water employs all three types of reactions, i.e., precipitation, acid-base, and redox-reactions.
Precipitation reaction involves formation of :

Options

A. insoluble `MgCO_(3)` by adding `Na_(2)CO_(3)`
B. insoluble `Mg(OH)_(2)` by adding `Ca(OH)_(2)`
C. insoluble in `MgSO_(4)` by adding `Na_(2)SO_(4)`
D. insoluble `MgCl_(2)` by adding NaCl

Answer

B