选C don't have to 不必迫于做某事（表示不受客观条件的限制）
have not 和haven't没有区别,都是现在完成事态的否定用法.haven‘t是缩写
e.g.:I have finished my homework
变否定：i have not finished my homework
变疑问：have you finished your homework?
句子意思为 冬天没必要戴眼镜.