some people regard as a disadvantage is seen as an advantage by many others. A. WhetherB.

问题补充：

some people regard as a disadvantage is seen as an advantage by many others.

A. Whether

B. What

C. That

D. How

答案：

A. Whether

(答案→)B. What

C. That

D. How

解析：考查从句，What引导的主语从句，Whether表示是否，That只起引导作用，没有任何意义，How关系副词，表示怎么，句子意思“一些人把什么都当做缺点被其他人看成是优点”，固定词组regard as意思“看做”