A Student was asked to calculate the surface area of a cube.
He calculated the volume.
The reason(s) of error in calculation is/are:
(a) the student finds the class boring as he does not like mathematics class
(b) the student is not fit to study in thet class
(c ) the student is not able to understand the concept of surface area and volume
(d) the student has understood the concept of surface area and volume
Select the correct answer using the code given below:

Options

A. (c )
B. (b) and (c )
C. (d)
D. (a) and (b)

Answer

To solve the question regarding the student's error in calculating the surface area of a cube instead of the volume, we can analyze the options provided and determine the correct reasoning behind the mistake.

### Step-by-Step Solution:

1. **Understanding the Problem**: The student was asked to calculate the surface area of a cube but mistakenly calculated the volume instead. We need to identify the reason for this error.

2. **Reviewing the Options**:
- (a) The student finds the class boring as he does not like mathematics class.
- (b) The student is not fit to study in that class.
- (c) The student is not able to understand the concept of surface area and volume.
- (d) The student has understood the concept of surface area and volume.

3. **Analyzing Each Option**:
- **Option (a)**: While finding the class boring may affect the student's attention, it does not directly explain the misunderstanding of the concepts.
- **Option (b)**: This option suggests a lack of fitness for the class but does not specify the understanding of the concepts involved.
- **Option (c)**: This option states that the student does not understand the concepts of surface area and volume, which directly relates to the error made in calculating the surface area instead of the volume.
- **Option (d)**: This option contradicts the situation since if the student understood the concepts, he would not have made the error.

4. **Conclusion**: The most relevant and logical reason for the student's error is option (c), which indicates a lack of understanding of the concepts involved.

5. **Selecting the Correct Answer**: Based on the analysis, the correct answer is option (c).

### Final Answer:
The correct answer is option (c): The student is not able to understand the concept of surface area and volume.