Number of dative bonds in the structure of ${\mathrm{SO}}_3$ molecule(not violating Octect rule) is/are

S(Z=16) , Ground state configuration is

One half filled ${\mathrm{sp}}^2$ orbital of 's' forms a $\mathrm{\sigma }$ bond with p-orbital of oxygen ;

One half filled p orbital of 'sulphur' forms a $\mathrm{\pi }$ bond with another p-orbital of same oxygen ;

Two ${\mathrm{sp}}^2$ orbitals each containing a pair of electrons  of 'S' form two dative bonds with two other oxygen atoms ;

Structure of ${\mathrm{SO}}_3$(not violating Octect rule) ;