The answer for the blank is buscamos.
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.
Yo He
Tu Has
Él/ella ha
Nosotros hemos
Ellas/ ellos han
Vosotros habéis
It’s à i was born in a Spanish family :)