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.
The answer is actually D. Neutral for the first one and C. Indigenous for the second one.
I know these are 100% correct because I just took the quick check. ;)