Which kind of fission is favoured by sunlight?

In which of the following,homolytic bond fission takes place?

The arenium ion which is not involved in the bromination of aniline is:

In the following reaction,compound $Q$ is obtained from compound $P$ via an ionic intermediate. What is the degree of unsaturation of $Q$?

Among the given compounds,the correct order of enol content is:
$(I)$ Cyclopentanone
$(II)$ $4$-hydroxycyclopent-$2$-en-$1$-one derivative
$(III)$ $\gamma$-butyrolactone derivative

In the given compound,how many sites are available for the attack of $CH_3O^{-}$?