Chemistry - Chemical Kinetics Question with Solution | TestHub

$\mathrm{A}(\mathrm{g})\to \mathrm{B}(\mathrm{g})+\mathrm{C}(\mathrm{g})$ is a first order reaction.
$\begin{array}{lll}\text{Time}& T& \infty \\ {\mathbf{P}}_{\text{system }}& {\mathrm{P}}_{\mathrm{t}}& {\mathrm{P}}_{\infty }\end{array}$
The reaction was started with reactant A only. Which of the following expression is correct for rate constant k ?