By the end of 1994, 558 kinds of products had been ______ green food.
问题描述：
By the end of 1994, 558 kinds of products had been ______ green food.
By the end of 1994, 558 kinds of products had been _____ green food.
选项:
a、named
b、restricted
c、classified
d、 labeled
答
选d、 labeled
到1994年底,558种产品被列为绿色食品.