PT 64 S3 Q16

Editorial: Cell-phone usage on buses and trains isannoying to other passengers. ... ...

Which one of the following most accurately describes the role played in the editorial’s argument by the statement that cell-phone use would be far more upsetting on airplanes than it is on buses and trains?
(A) It is the main conclusion of the argument.
(B) ...
(C) ...
(D) ...
(E) ...

*This question is included in Oct 2011 LSAT (PT 64): Logical Reasoning B