【单选题】

It is nearly 25 years since TheEconomist cooked up theBig Mac index. It was devised in September 1986 as a fun way to explain "purchasing-power parity", by comparing the prices of hamburgers in different countries.But burgernomics has since provided serious food for thought. Some economists think theBig Mac index has been surprisingly accurate in predicting long-run movements in exchange rates. It has also provided a few hot tips (and some half-baked ones) for investors.

When the euro was launched in 1999, almost everybody reckoned it would immediately rise against the dollar.But theBig Mac index suggested that the euro was already overvalueD、Soros Fund Management, a prominent hedge fund, later said that it sniffed at the sell smell coming from theBig Mac index, but resisted the temptation to bite. It was cheesed off when the euro promptly fell. Today, our burger barometer suggests that the euro is again overvalued against the other main currencies, and it highlights the euro area’s internal problems, showing that Greece, Italy, Portugal and Spain have lost competitiveness relative to Germany.
Burgernomics is also a handy check on whether governments are understating inflation. It supports claims thatArgentina has been cooking the books: over the past decade,Big Mac prices there have, on average, risen by well over ten percentage points more each year than the official consumer-price index—a far bigger gap than in any other country.But bingeing on burgernomics can be unhealthy.American politicians cite theBig Mac index as proof that the yuan is massively undervalueD、It is true that burgers are cheap inChina, but so they should be in all emerging economies, because wages are much lower. If the index is adjusted for GDP per person, it shows that the yuan is now close to its fair value against the dollar.
Studies suggest that theBig Mac index fairly closely tracks the purchasing-power-parity rates calculated by more sophisticated methods. Yet whereas those fancier techniques require researchers to gather thousands of prices in each country and take two years to produce, theBig Mac index relies on a single product, so the results are almost instant.
Official economic statistics are published only after a lag and are subject to big revisions. This explains the popularity of some quirky but timely indicators. WhenAlan Greenspan was chairman of the Federal Reserve, he monitored several unusual measures. One favourite, supposedly, was sales of men’s underwear, which are usually pretty constant, but drop in recessions when men replace them less often. The Old Lady of Threadneedle Street is perhaps too prim to inspect men’s underpants. Instead, theBank ofEngland tracks data on internet searches for telltale terms. It has, for example, found that the trend in searches for "estate agents" can be a predictor of house prices.
The example of Soros Fund Management proved that
A、theBig Mac index’s indication as to euro’s value was trustworthy.
B、there were some obvious problems within the euro areA、
C、euro’s value increased as everyone expecteD、
D、the firm benefited a lot from theBig Mac index’s predication.