The $K_{a}$ values of $A$,$B$,and $C$ are $1.8 \times 10^{-4}$,$5 \times 10^{-10}$,and $3 \times 10^{-8}$ respectively. The correct order of their acidic strength is

• A
  $B > A > C$
• B
  $B > C > A$
• C
  $A > B > C$
• D
  $A > C > B$