a
\((a)\) According to Huckel rule for aromaticity the molecule must be planar, cyclic system having delocalised \((4n + 2) \,\pi\) electron where \(n\) is an integer equal to \(0, 1, 2, 3,\) thus the aromatic comp. have delocalised electron cloud of
\(2, 6, 10\) or \(14\) \(\pi\) electron cyclopropenyl cation have the \(2\) \(\pi\) electron \((n = 0)\) so it is aromatic.
