Since u don't have any choices I would say FUERON
You didn't specify the tense or the subject, so I'll just use present tense.
1. Estudio porque me gusta la escuela. (I study because I like school)
2. Me mejor amigo es Leo. (My best friend is Leo)
3. Él come mucha comida. (He eats a lot of food)
4. Mi profesor habla mucho. (My teacher talks a lot)
5. Nací en dos mil. (I was born in 2000)
The answer would be anoche. I hope that helped
