A trisubstituted compound ‘A’, \( \mathrm{C_{10}H_{12}O_2} \) gives neutral \( \mathrm{FeCl_3} \) test positive. Treatment of compound ‘A’ with \( \mathrm{NaOH} \) and \( \mathrm{CH_3Br} \) gives \( \mathrm{C_{11}H_{14}O_2} \), with hydroiodic acid gives methyl iodide and with hot conc. \( \mathrm{NaOH} \) gives a compound B, \( \mathrm{C_{10}H_{12}O_2} \). Compound ‘A’ also decolorizes alkaline \( \mathrm{KMnO_4} \). The number of \( \pi \) bond(s) present in the compound ‘A’ is ________.