Answer:
The sentence "C: Tony picked up the tab for our dinner last night. " is written using informal language.
Step-by-step explanation:
Informal language means the one that is spoken casually and used amongst family and friends. It is not a formal language used in offices and businesses.
Option C has a word ‘tab’ which is a casual word for ‘tablet’. So, this is a sentence in informal language. Other options have all formal words used. For example, ‘detoured’ in option A. Option B refers to fire drill. Option D refers to the menu that was ‘impressive’.