Answer:
What to do? What do you need help with specifically?
(Translation of directions? explanations? )
Explanation:
<em>Bonjour ! </em>
Boris : Alors, Cathy ! Comment ça va au lycée ? Il est important que tu "étudies" sérieusement, tu sais.
Bonjour,
Non, je ne joue pas bien aux échecs.
Hello!
The key here is formal v. informal. Célèbres is informal, while <span>célébrez is formal. The phrase in question uses tu which is the informal version of "you", vous being the formal version.
The correct verb for tu is </span><span>célèbres. The answer is a.
Hope this helps!</span>