Which of the following lines creates a natural pause by using an em dash correctly?

"I—uh—am confused. Weren’t we leaving at noon?" asked Carla.
"Let’s sit over—watch out!" yelled Bianca as the Frisbee passed over Nawal’s head.
"My salad is filled with sand!" shrieked—Lara.
"I don’t know what happened, suddenly— " —exclaimed Ned.