New graduates in America are used to facing an uncertain future while saddled with heavy debts.Now Sallie Mae，the firm that provides many of them with the financial wherewithal to complete their education，will understand how they feel.On Monday April 16th it was announced that two private-equity firms along with two banks，JPMorgan Chase and Bank of America，had agreed to pay $25billion for America’s leading student-loan provider.
In the past decade the market for student loans has doubled to around $85billion a year.Student numbers have swelled while incomes have failed to keep pace with the soaring cost of college education.Sallie Mae has over a quarter of the entire business in America.And though margins are wafer-thin the firm made a profit of $1.2billion last year.
This profitability has attracted the interest of both Democratic and Republican lawmakers，seeking ways to save money while making education more affordable.Particularly vulnerable is the proportion doled out to big and profitable private companies like Sallie Mae to subsidise affordable government-backed loans.These now account for around 85%of its lending.
Sallie Mae’s profits and healthy cash-flow are a draw for private equity.And the involvement of the two banks could prove useful for plugging any gap in financing，if the firm’s credit rating slips following the assumption of so much debt.It helps that Sallie Mae is also making money beyond its core business.The market for private loans，without government subsidies or guarantees，is growing fast as the cost of education grows while the size of federal loans that students can take out has remained flat.This sort of loan is nicely profitable because lenders can levy high interest rates.New graduates are also targets：Sallie Mae has built a big debt-collection arm for reluctant repayers and a college-fund business for fast breeders.
Even the renewed interest from politicians could play into Sallie Mae’s hands.The lure of profits over the past decade has drawn more lenders into the business.Any future regulations or legislation that might shave profit margins further could deter new entrants or force smaller lenders out of the business，and Sallie Mae may get more opportunities to offset the reduction.But despite all the safeguards，students are high risk borrowers who quickly amass big debts.Sallie Mae，like many of the students it serves，could wake up one day with a nasty hangover（拖欠）and little recollection about how it came about.

The example of Sallie Mae Company is used by the author to （）

A．express the current situation of student-loan.
B．describe the banking industry of the U.S.
C．show problems in politics.
D．talk about the environment of education in the U.S.