Answer: The first sentence is B. Le. The second sentence is C. Les. The third sentence is D. Te. The fourth sentence is A. Nos.
Explanation: The first sentence is Le because it is in the Usted form. The second sentence is Les because there are two people, and the answer needs to be plural. The third sentence is Te because it is in the tú form. The fourth sentence is Nos because a person plus yourself is in the nosotros form.
Tu can be used when you're like talking to a friend or a family member or classmate and usted is used in a more formal way. For example, if you were talking to your doctor or teacher you would use usted.
