1:47 and E.
A. I almost thought it was a contender but not the best choice. Here,
the author does give some kind of additional empirical evidence to discredit the claim(50% of B live under poverty). But just giving any econominc advice is not enough to discredit the claim. It has to be valid.
B. I think this answer is just to distract us
C. This possibility does not make the argument vulnerable. The population of the two countries could be same and the % of people living under poverty could still differ.
D. Another distraction.
Best choice is E. All the incomes in country K are near average, and incomes in country B could widely vary from the average. This is a possibility that makes the argument weak/vulnerable.
I'm crossing the bridge.........