Réponse :

a. Jenny and Chris are not (aren't) baking cupcakes today.

Are Jenny and Chris baking cupcakes today ?

b. You're not making a mistake!

Are you making a mistake ?

c) She isn't watching a movie with her friends.

Is she watching a movie with her friends ?

d. The policeman isn't running after a criminal.

Is the policeman running after a criminal?