Point P lies at equatorial positions of dipole 1 and 2 and axial position of dipole 3.
Hence, field at P due to dipole 1 , E1=x3k⋅p (towards left)
Due to dipole 2 , E2=x2k⋅p (towards left)
Due to dipole 3,E3=x3k(2p) (towards right)
So, net field at P will be zero.