The correct answer is      (D.) DaVita (DVA)

Dialysis (a chemical process that removes unwanted substances from blood) is the only part of the health-care system that operates under a "single-payer" system -- the government pays for almost all of the treatments. In 1972, the federal government made a unique change to Medicare. Kidney failure diagnoses made any patient eligible for Medicare coverage of prescribed treatments, regardless of age. But if the patient has employer-provided health coverage, Medicare doesn't kick in as the primary payer until after the first 30 months.

And because about 11.5% of adults older than 20 -- some 23 million people -- have some type of chronic kidney disease and 355,000 are on dialysis, it's a strong business that will see more patients as the population ages.

Medicare pays about $235 per treatment -- this, admittedly, is a simplification of a very complex reimbursement schedule -- but private insurance pays a multiple of that, perhaps as much as five or even ten times. Dialysis providers actually make their profit from patients covered by private insurance, about 35% of the total. There's a steady supply of new patients: In 2006, for example, 110,854 people across the country started dialysis. These are the profitable cases that drive the industry's profits, before they become low- or no-margin Medicare beneficiaries after 30 months. From time to time, Washington threatens to decrease Medicare's coverage of dialysis and increase the number of months that patients must use their private insurance. Though it's rare to hear about cutting a government program, it would allow DaVita to charge its higher private-insurance rate for a longer period.

DaVita's long-term results are a textbook example of how to build shareholder value. In the past 10 years, shares of DVA have returned an annualized +24.5%, about twice the average historical return of the S&P. The firm already serves about 22% of the U.S. market in an industry with high barriers to entry, and the company delivered a compound annual growth rate of +14.6% in the past ten years, during which time operating income grew at a +19.0% annual clip. That's why StreetAuthority editor Andy Obermueller added DVA to his Government-Driven Investing Portfolio. But DVA isn't Andy's only pick this month -- he's also identified five other stocks poised to capitalize on existing and potential changes in various government programs. To learn the names of Andy's picks, and to learn more about Government-Driven Investing, please visit this link.