Answer:
Yo: Soy
Tu: Eres
Ella/El/Usted: Es
Ellas/Ellos/Ustedes: Son
Nosotros: Somos
Vosotors: Sois
Explanation:
Ser is an irregular verb in almost all tenses in Spanish. This means that the conjugations for ser are different that regular conjugations - you don't conjugate it like you would with any other -er verb. These are the conjugations for each form.
Hope this helps.