The plot that represents the zero order reaction is:

Options

A.
B.
C.
D.

Explanation

To determine the plot that represents a zero-order reaction, we can follow these steps:

### Step 1: Understand Zero-Order Reactions
In a zero-order reaction, the rate of reaction is constant and does not depend on the concentration of the reactant. This means that the rate of reaction remains the same regardless of how much of the reactant is present.

### Step 2: Write the Rate Law
For a zero-order reaction, the rate law can be expressed as:
\[ \text{Rate} = k \]
where \( k \) is the rate constant.

### Step 3: Relate Concentration to Time
For a zero-order reaction, the concentration of the reactant \( [A] \) decreases linearly over time. The relationship can be expressed as:
\[ [A] = [A_0] - kt \]
where:
- \( [A] \) is the concentration at time \( t \),
- \( [A_0] \) is the initial concentration,
- \( k \) is the rate constant,
- \( t \) is time.

### Step 4: Plotting the Graph
If we plot the concentration of the reactant \( [A] \) versus time \( t \), we will get a straight line with a negative slope. This indicates that the concentration decreases linearly over time.

### Step 5: Identify the Correct Plot
Since the concentration decreases linearly, the plot of \( [A] \) vs. \( t \) will be a straight line. The plot that represents the zero-order reaction is a straight line with a negative slope.

### Conclusion
The correct answer is that the plot representing a zero-order reaction is a straight line with a negative slope when plotting concentration vs. time.

---