Which of the following words does NOT have suffixes? （）

Which of the following words does NOT have suffixes? （）
A、Northward.
B、Widen.
C、Happy.
D、Worker.
【正确答案】：C
【题目解析】：Northward 的后缀是-ward表示向着…. Widen 的后缀是-en 放到形容词后，使之变成动词。 Worker 的后缀是-er表示“….的人”