OG语法29题，动名词修饰的从句/动名词结构前一定要加主语吗？

janetblcu

好像是第二次在同一个问题上犯错。
Emily Dickinson's letters to Susan Huntington Dickinson were written over a period beginning a few years before Susan's marriage to Emily's brother and ending shortly before Emily's death in 1886, outnumbering her letters to anyone else.
(A)Dickinson were written over a period beginning a few years before Susan's marriage to Emily's brother and ending shortly before Emily's death in 1886, outnumbering
(B)Dickinson were written over a period that begins a few years before Susan's marriage to Emily's brother and ended shortly before Emily's death in 1886, outnumber
(C)Dickinson, written over a period beginning a few years before Susan's marriage to Emily's brother and that ends shortly before Emily's death in 1886 and outnumbering
(D)Dickinson, which were written over a period beginning a few years before Susan's marriage to Emily's brother, ending shortly before Emily's death in 1886, and outnumbering
(E)Dickinson, which were written over a period beginning a few years before Susan's marriage to Emily's brother and ending shortly before Emily's death in 1886, outnumber
OG对A的解释有两点：1、开头太长啰嗦；2、不知道outnumbering修饰什么。

关于解释的第二点有些疑问，难道outnumbering不是修饰Emily Dickinson's letters么。