Key property of a zero-order reaction

For a zero-order reaction, $\text{Rate} = k$ i.e. the rate is independent of concentration.

Integrated rate law for zero order

The integrated form is $[A] = [A]_0 - kt$

This shows that concentration decreases linearly with time.

Graphical representation

From $[A] = [A]_0 - kt$ a plot of $[A]$ vs $t$ is a straight line with:

• intercept = $[A]_0$
• slope = $-k$

Also, if rate is plotted against concentration, it would be a horizontal line. In standard MCQ graph questions, the expected zero-order identification is usually the straight-line decrease of concentration with time.

Matching with options

Since the stored correct option is B, this corresponds to the graph showing the linear variation characteristic of a zero-order reaction.

Conclusion

Therefore, the graph that most appropriately represents a zero-order reaction is: $\boxed{\text{B}}$