She is the (elder) of the two sisters,but she is much (younger) than me.
按语法第一个比较级可以填 elder 或 younger
第二个可以填 younger 但不可填 elder
我们可以说
the elder of the two （两个人中年长的一个）
但不可说 much elder than
后者是病句
因此答案是 A.elder,younger
希望帮到了你,