C.intended to, intended to encourage children not to smoke and help people kick the habit为过去分词短语作定语,与The international agreement被动关系。
The international agreement是被用来encouraged children 的 所以要用被动
be intended to do sth打算做某事,过去分词作状语,表状态;也可理解为-ed形容词作状语。
encourage!