Answer:
D. Are you gonna come, or what?
Step-by-step explanation:
Informal tone refers to the informal way of telling or saying anything. Informal language includes slang, broken syntax and various figures of speech. An informal way of writing includes the way of the writing things as it would be said in a conversation. In the given sentences, the first three sentences are written in the formal tone. The last sentence is an example of an informal way of writing. The syntax used in the sentence makes it an informal sentence.