At a party, it's sometimes permissible for serving personnel to

Asmoke, provided they don't do so in view of the guests.
Bbecome part of the party if they know some of the guests.
Ctake home any leftovers that remain.
Dsample the buffet items before the guests arrive.

Verified Answer :

The correct answer is letter A. At a party, it's sometimes permissible for serving personnel to smoke, provided they don't do so in view of the guests. There are designated areas where people are allowed to smoke because we can not really deny and avoid that there are people who really wanted to smoke.

Hagrid

At a party, it's sometimes
permissible for serving personnel to sample the buffet items before the guests
arrive. The answer is letter D. This is to ensure that the food they are
serving will fit with the taste of the guests.