Answer:
Vayas
Step-by-step explanation:
In this sentence, the present subjunctive is used. This is a tense that is used for dependent clauses after an expression where the verb is in present or future. The conjugation of the verb ir is:
Yo vaya
tú vayas
El, ella, Usted vaya
Nosotros vayamos
Ellos, ellas, Ustedes vayan
According to this, the correct form of the verb ir with the pronoun tu is vayas, so that is the correct answer.