For a reaction $R \rightarrow P$ with a rate constant of $3 \times 10^{-3} \mathrm{~mol} \mathrm{~L}^{-1} \mathrm{~s}^{-1}$, which one of the following plots is correct? (Given [R] $]_0$ is the initial concentration of $R$ and $[R]$ is the concentration of $R$ at time t)

A first-order reaction is found to have a half-life of one second (sec). What will be the time required for $99.9 \%$ completion of the reaction?