Which entity is they this sentence?

Monster trucks would crush cars since they are so massive.

OPTIONS:
- Monster trucks
- cars
Monster trucks
Vilket väsen är det här straffet? Monstertruckar skulle krossa bilar eftersom de är så massiva. Alternativ: - Monster lastbilar - bilar
What entity is this punishment? Monster trucks would crush cars because they're so massive. Options: - Monster trucks - cars
Monstertruckar
Fork-lift trucks