听力原文：The Mexican economy went of a cliff in the second three months of 2009, with the

听力原文： The Mexican economy went of a cliff in the second three months of 2009, with the Gross Domestic Product dropping 10. 3% from the same period last year, according to government 'figures. Analysts say the main cause of Mexico's nosedive is that the nation's economy is tied strongly to that of the United States, which is mired in the deepest economic downturn since the 1930s. Other factors dragging the Mexican economy down include a tourism decline caused by the H1N1 flu outbreak, declining oil and tax revenues, and fewer Mexicans abroad sending money back home. (9) Oil revenues, long Mexico's main source of money, have been hurt by lower global prices and declining production. Remittances from Mexicans working abroad, most of them in the United States, also have fallen victim to the economic downturn. Fewer jobs in the United States mean fewer opportunities for Mexicans to find work and send money home. (10) Remittances rank after oil in terms of revenue for the country. That revenue fell from $ 26 billion in 2007 to $ 25 billion in 2008, Mexico's central bank said, and is expected to decrease even more this year. Tourism, Mexico's third largest source of revenue, has declined steadily, since an outbreak of the H1N1 flu was first discovered in Mexico in April.

Which of the following is NOT mentioned as a cause of the current decline in the Mexican economy？

A．Strong ties with the U. S. economy.

B．Fewer job opportunities in Mexico.

C．Decline in tourism.

D．Decline in tax revenues.