Which of the following statements is true?

In the reaction,$A + B \to C + D$,the rate $\left( \frac{dx}{dt} \right)$ when plotted against time $t$ gives a straight line parallel to the time axis. The order and rate of reaction will be

What is the value of the slope of a graph obtained by plotting the concentration of reactant $[A]_t$ versus time for a zero order reaction?

For a zero order reaction,the plot of concentration of reactant $vs$ time is (Hint: Consider the intercept on the concentration axis)

When the initial concentration of the reactant is doubled,the half-life period of 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 $A$ $(mol \ L^{-1})$ |
| :--- | :--- |
| $0$ | $0.1$ |
| $15$ | $0.05$ |
| $20$ | $0.1 - x$ |