The rate equation for a reaction, \[{{N}_{2}}O\xrightarrow{{}}{{N}_{2}}+1/2{{O}_{2}}\] is Rate \[=k{{[{{N}_{2}}O]}^{0}}=k.\] If the initial concentration of the reactant is a mol\[Li{{t}^{-1}}\], the half-life period of the reaction is

• A. \[{{t}_{\frac{1}{2}}}=\frac{a}{2k}\]                
• B. \[-{{t}_{\frac{1}{2}}}=ka\]
• C. \[{{t}_{\frac{1}{2}}}=\frac{a}{k}\]                  
• D. \[{{t}_{\frac{1}{2}}}=\frac{k}{a}\]