I'm going to say B as well.
Facts:
- some airlines reduce fairs to drive away competition
- this method is bad for the long run
- (argument) bad strategy b/c companies would need to increase prices to sustain profits, giving competitors a chance to undercut their prices
We need to attack (weaken) the argument.
(a) references other countries and something about legal vs. illegal. this is all new info not mentioned in the original passage.
(b) restates key points in the original passage and addresses how companies can keep competitors away. key part of the argument was that competitors would re-emerge.
(c) never mentions anything about promotions to attract new customers.
(d) original passage says nothing about shifting resources or reducing the size of operations
(e) doesn't address the argument that competitors would re-emerge