关于in的用法？

23. Oberlin
                    College in Ohio was a renegade institution at its 1833 founding for deciding to accept both men and women as students.
(A) at its 1833 founding for deciding to accept
(B) for the decision at its 1833 founding to accept
(C) when it was founded in 1833 for its decision to accept
(D) in deciding at its founding in 1833 to accept
(E) by deciding at its founding in 1833 on the acceptance of

答案是D，为什么呢？in在这里是什么用法？我觉得C挺不错的啊。欢迎探讨