All the people ________ at the party were his supporters．

A.present

B.thankful

C.interested

D.import

答案及解析： A

解析：

题意为“所有出席宴会的人都是他的拥护者”。be present at“出席……”作定语时，省去“be present at”作了后置定语，be interested in“对……感兴趣的”，故只能选A。