Which of the following graphs most appropriately represents a zero order reaction?

What is the correct relation between rate constant and half-life for a zero order reaction?

For a reaction,doubling the concentration of the reactant doubles the half-life period. What is the order of the reaction?

The decomposition of $NH_3$ on a platinum surface is a zero-order reaction. What is the rate of production of $N_2$ if $k = 2.5 \times 10^{-4} \ mol \ L^{-1} \ s^{-1}$?

For a zero order reaction,the plot of concentration $(a-x)$ $Vs$ time is linear with

For a reaction of $n^{th}$ order,the plot of $t_{1/2}$ versus initial concentration $[A]_0$ is a straight line. When the initial concentration is $2 \ mol \ L^{-1}$,the reaction takes $10 \ min$ to complete $50\%$. If the reaction takes $t \ min$ to complete $50\%$ when the initial concentration is $4 \ mol \ L^{-1}$,find $n$ and $t$ respectively.