Analyze the following sentences and decide which one is given in a closing one.
选项：

A:On behalf of my colleagues, I wish you all a convivial welcome.;
B:We are honored to invite some distinguished experts to give plenary speeches.;
C:Now the conference is closed. Our next conference will be held in Beijing. I am looking forward to meeting you again!;
D:I wish the conference will be successful and productive, and wish you to have a very pleasant and memorable experience in the beautiful and historical city of Changsha.