Which statement is correct regarding a zero order reaction?

What is the concentration (in $mol \ L^{-1}$) of the product $B$ after $20 \ s$ in the following reaction? Given that $A \longrightarrow 3B$,rate $= k[A]^0$. The data is provided in the table below:
| Time $(s)$ | Concentration of reactant $A$ $(mol \ L^{-1})$ |
| :--- | :--- |
| $0$ | $0.1$ |
| $15$ | $0.05$ |
| $20$ | $0.1 - x$ |

If the rate of the reaction is equal to the rate constant,the order of the reaction is

The rate constant,$k$ of a zero order reaction $2 NH_{3(g)} \xrightarrow[1130 \ K]{Pt} N_{2(g)} + 3 H_{2(g)}$ is $y \times 10^{-4} \ mol \ L^{-1} \ s^{-1}$. The rate of formation of hydrogen (in $mol \ L^{-1} \ s^{-1}$) is

Calculate the half life $(t_{1/2})$ and completion time $(T)$ for a zero order reaction if $K = 0.001 \, mol \, L^{-1} \, sec^{-1}$ and initial concentration $(a) = 1 \, M$.

If the initial concentration is reduced to its $1/4^{th}$ in a zero order reaction,the time taken for half of the reaction to complete