Answer: This public service announcement is trying to persuade people to wear seat belts.
Explanation: In this public service announcement, <u>a seat belt is conceived as a good friend since it is capable of protecting people</u>. Therefore, the announcement is highlighting a positive aspect of wearing seat belts. The last sentence (and more specifically the clause "they are supposed to wear seat belts") is the one that mainly shows the main purpose of this announcement: persuading people to wear seat belts.
