Which is the correct expression for half-life [CBSE PMT 2000]

• A.            \[{{(t)}_{1/2}}=\log 2\]    
• B.            \[{{(t)}_{1/2}}=\frac{\lambda }{\log 2}\]
• C.            \[{{(t)}_{1/2}}=\frac{\lambda }{\log \,\text{2}}(2.303)\]     
• D.            \[{{(t)}_{1/2}}=\frac{2.303\text{ log 2}}{\lambda }\]