Who is they in the following sentence?

Monster trucks would crush cars since they are so much smaller in size.

OPTIONS:
- Monster trucks
- cars
cars
Vilka är de i följande mening? Monster lastbilar skulle krossa bilar eftersom de är så mycket mindre i storlek. Alternativ: - Monster lastbilar - bilar
Who are they in the following sentence? Monster trucks would crush cars because they are so much smaller in size. Options: - Monster trucks - cars
bilar
cars