I just figure it our myself. it is my bad. Thanks anyway!

Editorial:

The mayor plans to deactivate the city’s fire alarm boxes, because most calls received from them are false alarms. The mayor claims that the alarm boxes are no longer necessary, since most people now have access to either public or private telephone. But the city’s commercial district, where there is the greatest risk of fire, has few residents and few public telephones, so some alarm boxes are still necessary.

Which of the following, if true, most seriously weakens the editorial’s argument?

(A) Maintaining the fire alarm boxes costs the city more than five million dollars annually.

(B) Commercial buildings have automatic fire alarm systems that are linked directly to the fire department.

(C) The fire department gets less information from an alarm box than it does from a telephone call.

(D) The city’s fire department is located much closer to the residential areas than to the commercial district.

(E) On average, almost 25 percent of the public telephones in the city are out of order.

The best answer is B

B "weakens the editorial’s argument"