$Ba$,$Ca$,and $Sr$ form halide hydrates. Their formulas are $BaCl_2 \cdot x H_2 O$,$CaCl_2 \cdot y H_2 O$,and $SrCl_2 \cdot z H_2 O$. The values of $x$,$y$,and $z$ respectively are:

• A
  $2, 6, 6$
• B
  $8, 6, 2$
• C
  $8, 6, 6$
• D
  $6, 4, 2$