Welcome speech of the school delegation

A. This slogan is used properly, showing the welcome and attention to the other party.

B. This information is used appropriately, expressing encouragement to the students.

C. "gift" is a kind of compliment, which means that the other party gives (property), so it is not appropriate to use it here.

D. the postscript is appropriate to show respect for Mr. Ji.

So choose: C.