A city corporation reports that in the six months since the sorting of household waste was made compulsory in Ward 14, the quantity of mixed waste reaching the dumping ground from that ward has fallen by a third, and concludes that Ward 14's households are now sorting their waste. Which of the following, if true, most weakens the corporation's conclusion?

Less waste arriving at the dumping ground is what sorting would produce and equally what waste going into the lanes and the nala instead of into the lorry would produce, and the option supplies both the reason for the second and the sight of it. The corporation's figure therefore fails to tell a ward that sorts from a ward that dumps. The handbill is a reason to expect the rule to have been understood and so tells for the corporation. The third option merely says over again what the report has already said — a fall in mixed waste at the dumping ground — and repeating a premise neither supports a conclusion nor damages it. That the rule covers the whole city describes its reach and leaves Ward 14's figure meaning whatever it meant before.