Question

5.

Answer 1

The answer is : It highlights the contrast between the Dursley's excitement for the dinner and Harry's loneliness.

Harry is a lonely boy as he must remain outcast and invisible to Dursley's visitors. During this time, Dursleys are expecting some visitors which has relation to Vernon's job. Harry must stay in the bedroom so the visitors won't see him and won't ask some things about him. Since they are having a visitor, a dinner must be served to make the visit worthwhile which is what the Dursleys are looking forward to.