关于正确选项的疑问

witty1

A letter by Mark Twain, written in the same year as The Adventures of Huckleberry Finn were published, reveals that Twain provided financial assistance to one of the first Black students at Yale Law School.
(A) A letter by Mark Twain, written in the same year as The Adventures of Huckleberry Finn were published,
(B) A letter by Mark Twain, written in the same year of publication as The Adventures of Huckleberry Finn,
(C) A letter by Mark Twain, written in the same year that The Adventures of Huckleberry Finn was published,
(D) Mark Twain wrote a letter in the same year as he published The Adventures of Huckleberry Finn that
(E) Mark Twain wrote a letter in the same year of publication asThe Adventures of Huckleberry Finn that

正确答案C中关系代词that有些疑惑？不应该用in which或when吗？that仅指代year，不指代in the same year吧？跪求解答....

witty1

谁能抽空发表一下高见呢？万分感激呐！