Answer:
vas
Step-by-step explanation:
We are given the verb ir, which we want to conjugate in the second-person singular (tú, which is 'you' (informal)).
ir is an irregular verb, meaning that its forms are different from other verbs ending in ir.
In the present tense, ir has the following conjugations:
yo voy
tú vas
él/ella/usted va
nosotros vamos
vosotros vais
Ellos/ellas/ustedes van
Because of this, the correct conjugation for the tú form is vas.
Why does ir have these conjugations?
Ir in Spanish is really a combination of two Latin verbs: ire, which is 'to go', and vadere, which also means 'to go'. The present conjugations come from vadere (hence the 'va' at the start of most of the conjugations).