Taylor Swift Or Ariana Grande Quiz: Who Sang It?

Ariana Grande performs at the KIIS FM's Jingle Ball at the Staples Center on Friday, Dec. 5, 2014, in Los Angeles. (Photo by John Shearer/Invision/AP)
John Shearer/AP

14. "Shut Your Mouth, And If You Don't Know That Now You Know It, Babe"

Taylor Swift

Ariana Grande
Contributor

Dennis Thomas hasn't written a bio just yet, but if they had... it would appear here.