Nell is writing a short story. Read the following excerpt.

Keisha’s heart raced as she waited for her turn to go onstage. She had practiced her dance routine hundreds of times, but she was terrified that she would slip and fall in front of the large audience, which included her dance teacher and her whole extended family. Finally Keisha took a deep breath and trotted to center stage behind the curtain, striking a fierce pose.

Which addition to the story would add an element of dramatic irony?

A.
Keisha’s performance went off without a snag. Afterward, even her twin brother Colin congratulated her: “You didn’t even slip and fall down!” he joked.
B.
Keisha danced flawlessly and finished with a grin. As she took her bows, she slipped and landed hard on her tailbone—she hadn’t practiced that part.
C.
As the music began, Keisha moved gracefully around the stage. She did slip once but recovered with a smile, confident that the audience did not notice.
D.
Backstage, Keisha’s twin brother Colin chuckled quietly to himself. Above the curtain he had perched a large bucket of water—perfect for dousing his sister and the stage.