Find the class mark of the class `90-120`.

Options

A. `100`
B. `101`
C. `104`
D. `105`

Explanation

To find the class mark of the class `90-120`, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Upper and Lower Limits**:
- The lower limit of the class is 90.
- The upper limit of the class is 120.

2. **Use the Formula for Class Mark**:
- The formula to find the class mark (or midpoint) is given by:
\[ \text{Class Mark} = \frac{\text{Upper Limit} + \text{Lower Limit}}{2} \]

3. **Substitute the Values into the Formula**:
- Substitute the upper limit (120) and lower limit (90) into the formula:
\[ \text{Class Mark} = \frac{120 + 90}{2} \]

4. **Calculate the Sum of the Limits**:
- First, calculate the sum of the upper and lower limits:
\[ 120 + 90 = 210 \]

5. **Divide the Sum by 2**:
- Now, divide the sum by 2 to find the class mark:
\[ \text{Class Mark} = \frac{210}{2} = 105 \]

6. **Conclusion**:
- Therefore, the class mark for the class `90-120` is **105**.