It is hot outside, but your parents have been sitting outside of school with the car's engine running. the door handle on the car feels hot, but when you get inside, the car is cool because of the a/c. is the car an open or closed system?

it takes about 30 days for it to break down

i am pretty sure it is c because when people are closer together, they cannot move as freely. picture being in a mostly full elevator, for instance. the people are right next to you, and you can barely move.