The major product formed in the given reaction is:

Nitro group is electron-withdrawing group. Hence, increases the acidity of H atom (attached to C atom bearing nitro group).The removal of H becomes easy. Also, the newly formed double bond is in conjugation with nitro group.Note: In the given reaction, a molecule of HCl is lost and C=C double bond is formed.Thus, it is dehydrohalogenation reaction. The major product formed is represented by option (A).