Among the following the aromatic compound is

According to Huckel rule for aromaticity the molecule must be planar, cyclic system having delocalized (4n+2)pi electronsWhere n is an integer equal to 0,1,2,3 thus the aromatic compounds have delocalized electron cloud of 2,6,10 or 14 pi electronsIt has 2 pi electrons(n=0)So it is aromatic