Correct option is C
In organic chemistry, an electrocyclic reaction is a type of pericyclic, rearrangement reaction where the net result is one pi bond being converted into one sigma bond or vice versa. These reactions are usually categorized by the following criteria:
Reactions can be either photochemical or thermal.
Reactions can be either ring-opening or ring-closing (electrocyclization).
Depending on the type of reaction (photochemical or thermal) and the number of pi electrons, the reaction can happen through either a conrotatory or disrotatory mechanism.
The type of rotation determines whether the cis or trans isomer of the product will be formed.
