Commercial surveys have shown that the sales of ski sports equipment in City A is higher than that in City B. It can be seen that residents of City A prefer skiing more than residents of City B. If any of the following is true, it can most weaken the inference of the above investigation? ['y A. B has more population than City A.', 'A city ski equipment is produced in city B.', 'The winners of several national ski competitions came from city A.', 'In recent years, A city has vigorously developed tourism, and many tourists have learned skiing in A city.']