Given(i) \[HCN(aq)+{{H}_{2}}O(l)\rightleftharpoons \] \[{{H}_{3}}{{O}^{+}}(aq)+C{{N}^{-}}(aq){{K}_{a}}=6.2\times {{10}^{-10}}\](ii) \[C{{N}^{-}}(aq)+{{H}_{2}}O(l)\rightleftharpoons \] \[HCN(aq)+O{{H}^{-}}(aq){{K}_{b}}=1.6\times {{10}^{-5}}.\]These equilibria show the following order of the relative base strength,

• A. \[O{{H}^{-}}>{{H}_{2}}O>C{{N}^{-}}\]
• B. \[O{{H}^{-}}>C{{N}^{-}}>{{H}_{2}}O\]
• C. \[{{H}_{2}}O>C{{N}^{-}}>O{{H}^{-}}\]    
• D. \[C{{N}^{-}}>{{H}_{2}}O>O{{H}^{-}}\]