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

If doubling the initial concentration of reactant doubles $t_{1/2}$ of reaction,the order of reaction is

Which of the following is correct for a zero-order reaction?

Calculate the rate constant of a zero order reaction if it is $90 \%$ completed in $90 \ s$.

If the slope of a line of the graph between dissociated concentration of reactant $([A]_0 - [A]_t)$ and time ($t$ in $min$) for a zero order reaction is $0.02 \ mol \ L^{-1} \ min^{-1}$,then calculate the initial concentration of reactant $([A]_0)$,if after $30 \ min$ its concentration $([A]_t)$ is $0.05 \ mol \ L^{-1}$. (in $M$)

Which of the following graphs represents a zero order reaction?
($a = $ initial concentration of reactant,
$x = $ concentration of reactant consumed,
$t = $ time)