The decomposition of $N_2O_5$ is a first order reaction represented by $N_2O_5\rightarrow N_2O_4+\large\frac{1}{2}$$O_2$.After 15minutes the volume of $O_2$ produced is 9ml & at the end of the reaction 35ml.The rate constant is equal to

Question

$\begin{array}{1 1}(a)\;\large\frac{1}{15}\normalsize ln\large\frac{44}{35}&(b)\;\large\frac{1}{15}\normalsize ln \large\frac{35}{44}\\(c)\;\large\frac{1}{15}\normalsize ln\large\frac{44}{26}&(d)\;\large\frac{1}{15}\normalsize ln\large\frac{35}{26}\end{array}$