Which sentence uses dashes correctly?

A.
Now we will hike—along the ridge, down the hill, and across the creek.

B.
On the last page of my program is—the lead dancer's autograph.

C.
I want to hear everything, but—oh, someone is knocking on the door.

D.
This sweater—the one that turned up at the bottom of my closet, does not fit me anymore.