I still remember the day______I first came to the college.

I still remember the day______I first came to the college.
A.on which
B.in which
C.at which
D.which
2.,They will never forget the day ____they got married.
A.that B.which C.in which D.when
3.The factory ___his mother works is in the east of the city.
A.that B.which C.on which D.where
要写好理由啊