Cis-dicholoroethylene can be converted to trans-dichloroethylene by irradiation. During the
interconversion
(A) both the π and σ bonds are broken and reformed.
(B) only the π bond is broken and reformed.
(C) the C-Cl and C-H bonds are broken, H and Cl atoms interchange their positions and
new bonds are formed.
(D) both the π and σ bonds rotate along with the groups.