Number of structure isomer of C7H8O containing benzene :A 5 B 6 C 4 D 3

To determine the number of structural isomers of C7H8O containing benzene, we need to consider the different possible arrangements of atoms within the molecule.

1. Start by identifying the molecular formula: C7H8O. This tells us that the molecule contains 7 carbon atoms, 8 hydrogen atoms, and 1 oxygen atom.

2. Since we are specifically looking for isomers containing benzene, we know that one of the carbon atoms must be part of a benzene ring.

3. Benzene is a cyclic compound consisting of 6 carbon atoms and 6 hydrogen atoms. Therefore, we need to find a way to incorporate a benzene ring into the molecule.

4. One possible arrangement is to have the benzene ring attached to one of the carbon atoms in the C7H8O molecule. This would give us one isomer.

5. Another possibility is to have the benzene ring attached to a different carbon atom in the C7H8O molecule. This would give us another isomer.

6. We can continue this process by considering different arrangements of the benzene ring on the remaining carbon atoms in the C7H8O molecule.

7. By considering all possible arrangements, we find that there are a total of 3 structural isomers of C7H8O containing benzene.

Therefore, the correct answer is D) 3.