"K"

Knock, knock.
Q: Who's there?
A: Utah.
Q: Utah who?
A: Utah-king to me!?
Submitted, Becky, 11

Knock, Knock
Q: Who’s There?
A: Cass
Q: Cass Who?
A: Cass Toff, we’re leaving.

Knock, Knock
Q: Who’s There?
A: Donahue
Q: Donahue Who?
A: Donahue hide from me!

Knock-Knock
Q: Who’s there?
A: Lucinda.
Q: Lucinda Who?
A: Lucinda chain and let me inside.