People in many parts of the world like country music because

这句话从意思上看三个答案都成立
所以我们就要从词法和语法上来判断了
前文提到everyone knows,所以anything这个答案就被排除了,用anything的话应该搭配don't know anything
而从1和2选项里everything和something都是可以的,但是something更符合常理,如果everyone换成某一个人那么选择everything的可能性就更大