When a hydrocarbon A undergoes combustion in the presence of air, it requires \( 9.5 \) equivalents of oxygen and produces \( 3 \) equivalents of water. What is the molecular formula of A?
\( \mathrm{C}_9\mathrm{H}_9 \)
\( \mathrm{C}_8\mathrm{H}_6 \)
\( \mathrm{C}_6\mathrm{H}_6 \)
\( \mathrm{C}_9\mathrm{H}_6 \)