单选题 Which has been done by World Health Organization in combating the bad effects of influenza?

A、 Supervising the assessment of influenza virus strains.
B、 Holding meetings twice a year to provide the latest data concerning the composition of the vaccines.
C、 Publishing the related information in a WHO almanac.
D、 Stressing the importance of preventing influenza for people living in tropical areas of Asi

【正确答案】 A

【答案解析】文章第二段介绍了WHO所采取的措施，其中有：“monitor the evaluation of influenza virus strains”，即选项A；“an annual consultation at the end of February”，即每年一次的研讨会，为即将到来的流行病季节提供疫苗成分的建议，并且这些建议很快在流行病报告周刊上刊登出来，故排除选项B(一年举办两次会议，并提供最新数据)和选项c(把最新信息发布在WHO年鉴上)。选项D并未提及。