以下对结构类型变量的定义中不正确的是（ ）。

A、<IMG src="https://s3.cn-north-1.amazonaws.com.cn/qingshuxuetang/staticQuestionImg/be7d8f03-bace-4780-88b1-8f95958a8ee3.jpg"title="1374109374781.jpg" alt="1374109374781.jpg"/>&nbsp;

B、<IMG src="https://s3.cn-north-1.amazonaws.com.cn/qingshuxuetang/staticQuestionImg/9e22a0ef-4189-4381-8701-f2041c1cdd12.jpg"title="1374109385140.jpg" alt="1374109385140.jpg"/>

C、<IMG src="https://s3.cn-north-1.amazonaws.com.cn/qingshuxuetang/staticQuestionImg/cad50413-c59a-4a19-ad2b-c8c2e880bf74.jpg"title="1374109397031.jpg" alt="1374109397031.jpg"/>

D、<IMG src="https://s3.cn-north-1.amazonaws.com.cn/qingshuxuetang/staticQuestionImg/6f5a02fb-5063-4b1b-8cab-ce1426a3fc55.jpg"title="1374109407343.jpg" alt="1374109407343.jpg"/>