OE
You know that Burma was being mismanaged, so you want something bad (and appropriate to describe an economy). The blank and “isolation” are contrasted with “power and influence.” Just as isolation and influence are (somewhat) opposite ideas, you can expect the blank to oppose power: something like not powerful or not strong. Feebleness (weakness) is a good match. Monotony (lack of variety, tedious repetition) is negative, but no proof in the sentence supports this meaning. Opulence (wealth, abundance) is opposite of the desired meaning. Both nonchalance (casual lack of concern) and recriminations (counteraccusations) don’t make sense following “economic.”
Answer: D