Look at the figure given below and select the right option.
(a) a and b are sp3 orbitals and their side wise overlapping forms two π - bonds.
(b) c and d are two π - bonds concentrated around bond axis.
(c) c and d are two electron clouds of one π - bond and it is formed by the side wise overlap between two pz orbitals.
(d) c and d are two s - bonds formed by the lateral overlap of two pz orbitals.