Which sentence is written using formal language?

Responses
A Don't rattle her cage; Samantha has had a crummy day at work.Don't rattle her cage; Samantha has had a crummy day at work.
B You are out of your mind if you think I am flying in an airplane!You are out of your mind if you think I am flying in an airplane!
C I cannot believe it will take three hours to complete the transaction.I cannot believe it will take three hours to complete the transaction.
D Hey, could you toss me a pencil and some paper so I can complete this form? Hey, could you toss me a pencil and some paper so I can complete this form?

C I cannot believe it will take three hours to complete the transaction.