Please help with spanish

In the phrase un autobús con ovejas, ovejas means:

Read carefully and choose the option with the correctly written sentence. a mis sobrinas les gusta jugar la guitarra. a mis sobrinas le gustan tocar la guitarra. a mis sobrinas les gusta tocar la guitarra. a mis sobrinas le gustan jugar la guitarra.

Does anyone know what my spanish teacher means by this? i need to use plural forms of the verb ser. and she asked me to use a couple of adjectives to describe the boys collectively and then the girls collectively?