The text states two changes: burnable trash collection will be twice a week, and plastic bottles must be separated and put out on Fridays. The final sentence strongly warns that trash may not be collected if separation rules are not followed. This emphasizes the importance of the new separation rule for plastic bottles, making it the main point. Wrong answer 1 is incorrect ('once a week' vs. 'twice a week'). Wrong answer 2 is incorrect as time is not mentioned. Wrong answer 3 is the opposite of the new rule.