The maximum number of possible isomers (including stereoisomers) which may be formed on mono-bromination of 1-methylcyclohex-1-ene using Br₂ and UV light is ___________.

Total number of isomers, considering both structural and stereoisomers of cyclic ethers with the molecular formula C₄H₈O is .................

For the given compound $$X,$$ the total number of optically active stereoisomers is ____________.

Among the following, the number of aromatic compound(s) is