Every few years, the coal workers their lungs X-rayed to ensure their health.

Every few years, the coal workers                 their lungs X-rayed to ensure their health.

A.are having

B.have

C.have had

D.had had

答案及解析： B

解析：

考查时态。根据Every few years可知句子谓语要用一般现在时态。所以选B。