The rate constant of a first order reaction is given by :
(a) k = 2.303 \(\times\) t \(\times\) \(log_{10}\frac{a}{(a-x)}\)
(b) \(\frac{k}{t}\) = 2.303 \(log_{10}\frac{a}{(a-x)}\)
(c) k = \(\frac{2.303}{t}\)\(log_{10}\frac{1}{(a-x)}\)
(d) k = \(\frac{2.303}{t}\)\(log_{10}\frac{a}{(a-x)}\)