A. Many tire companies that are smaller than Tireworld have used nationwide campaigns to increase their profits.
If anything, this answer choice suggests that there is no flaw with the original argument.

B. Regional climatic conditions and local competition are extremely important factors in marketing tires.
BINGO! This suggests that moving to a nationwide marketing campaign will negatively impact REVENUE, since each region of the country has tire requirements specific to that region

C. During the last two years, Tireworld has sold ten percent of its tires to the military.
This provides no information (directly or indirectly) about REVENUE

D. Many tires are bought only in emergency situations, in which brand preferences are of little concern.
There's nothing here to suggest that moving to a nationwide marketing campaign will negatively impact REVENUE

E. Statewide tire-marketing campaigns often employ radio-advertisement stars in order to promote products.
A nationwide marketing campaign can still employ radio-advertisement stars in order to promote products

Answer: B