Which of the following is not isomers of `C_(8)H_(8)O` ?

Options

A.
B.
C.
D.

Explanation

To determine which of the given compounds is not an isomer of \( C_8H_8O \), we need to analyze the molecular formula of each compound provided in the options. Isomers have the same molecular formula but different structural arrangements.

### Step-by-Step Solution:

1. **Identify the Molecular Formula**: We are looking for compounds with the molecular formula \( C_8H_8O \).

2. **Analyze Each Option**:
- **Option 1**: Count the number of carbon atoms in the first compound.
- If there are 9 carbon atoms, then this compound cannot be an isomer of \( C_8H_8O \) because it does not match the required molecular formula.
- **Option 2**: Count the number of carbon and hydrogen atoms.
- If there are 8 carbon atoms and 8 hydrogen atoms, this compound matches the formula \( C_8H_8O \) and is therefore a valid isomer.
- **Option 3**: Again, count the carbon and hydrogen atoms.
- If this compound also has 8 carbon atoms and 8 hydrogen atoms, it is another valid isomer.
- **Option 4**: Count the carbon and hydrogen atoms.
- If this compound has 8 carbon atoms and the correct number of hydrogen atoms, it is also a valid isomer.

3. **Conclusion**: After analyzing all options, the compound with 9 carbon atoms is not an isomer of \( C_8H_8O \).

### Final Answer:
The compound that is **not an isomer of \( C_8H_8O \)** is the one with **9 carbon atoms**.

---