The number of single and double bonds present in a molecule of benzene $\mathrm{(C_6H_6)}$ respectively, are:

In a molecule of benzene ($\mathrm{C_6H_6}$), six carbon atoms are arranged in a ring with alternating single and double bonds.

• There are $3$ single carbon-carbon ($\mathrm{C-C}$) bonds and $3$ double carbon-carbon ($\mathrm{C=C}$) bonds in the ring.
• Each of the six carbon atoms is also bonded to one hydrogen atom via a single covalent carbon-hydrogen ($\mathrm{C-H}$) bond, contributing $6$ more single bonds.

Therefore:

• Total single bonds = $3\text{ (C-C)} + 6\text{ (C-H)} = 9$
• Total double bonds = $3\text{ (C=C)}$

Distractor Analysis:

• A (6 and 6): Incorrectly assumes there are 6 single bonds and 6 double bonds, which violates the tetravalency of carbon and monovalency of hydrogen.
• C (3 and 9): Reverses the actual count of single and double bonds.
• D (3 and 3): Only counts the bonds between the carbon atoms in the ring, completely neglecting the six single $\mathrm{C-H}$ bonds.