Final answer:
The biggest limitation of using an opinion column as a source is that it may contain biased information, which could undermine the credibility of a serious economic paper to be presented at a UN Committee.
Step-by-step explanation:
The most significant limitation of using an opinion column about the benefits of expanding international banks as a source for the economist's paper recommending that countries decrease regulations on international banks is B) the column may contain biased information. Opinion columns often reflect the author's personal viewpoint and may not be supported by rigorous data or analysis. For a recommendation being presented to the United Nations Economic and Financial Committee, it is essential that the source material is objective and backed by empirical evidence. A reliance on opinionated sources could undermine the credibility of the economist's argument.