Dear friends,
I met a problem that pronoun "his" stand for "Ryonosuke Akutagawa's", details as following:

Ryonosuke Akutagawa's knowledge of the literatures of Europe, China, and that of Japan were instrumental in his development as a writer, informing his literary style as much as the content of his fiction.

A) that of Japan were instrumental in his development as a writer, informing his literary style as much as

B) that of Japan was instrumental in his development as a writer, and it informed both his literary style as well as

C) Japan was instrumental in his development as a writer, informing both his literary style and

D) Japan was instrumental in his development as a writer, as it informed his literary style as much as

E) Japan were instrumental in his development as a writer, informing both his literary style in addition to

you see, his stand for "Ryonosuke Akutagawa's", can pronoun "his" stand for "Ryonosuke Akutagawa's"

it confused me a lot.

please help

thanks in advance
have a nice day
>_~