Correct Answer - `(a,b,c)`
Hofmann elimination gives less-substitued alkene.
a. Cope reaction
b. In case of buylky base, Hofmann alkene is formed
c. In case of `RF` (poor leaving group ) whether teh base is bulkyl or non-bulkyl. Hofmann alkene is formed.
`(I)` is more stable due to extended conjugation with `(=)` bond of `Ph-` ring.