At $27^{\circ} C$,the degree of dissociation of $HA$ (weak acid) in $0.5 \ M$ of its solution is $1 \%$. The concentrations of $H_3O^{+}$,$A^{-}$,and $HA$ at equilibrium (in $mol \ L^{-1}$) are respectively

• A
  $0.005, 0.005, 0.495$
• B
  $0.05, 0.05, 0.45$
• C
  $0.01, 0.01, 0.49$
• D
  $0.005, 0.495, 0.005$