In a first order reaction $[A \to B$ ], if $k$ is rate constant and initial concentration of the reactant A is 0.5 M then the half-life is :

Question

( A ) $\frac{\log 2}{k}$
( B ) $\frac{\log 2}{k \sqrt {0.5}}$
( C ) $\frac{0.693}{0.5 k}$
( D ) $\frac{ln2}{k}$