The correct answer is      (A.)  Slot Machines

Slot machines generate about two-thirds of Las Vegas casinos' revenues and an even higher percentage in other markets, such as Atlantic City. In Nevada, slot revenues surpassed those generated by blackjack and other table games in 1981 and never looked back.

And because players love slot machines, so do casino managers. Despite rising costs, a popular slot machine can pay for itself in a matter of weeks and requires little additional overhead -- no dealers or croupiers are needed. Plus, predetermined payback percentages ensure that the house hangs on to a large chunk of the cash.

You may have won a few coins from a slot machine, but there is a better way to make money with them: investing in the stocks of slot machine manufacturers. Just a few players dominate the market; in fact, casino operators get the vast majority of their slots from just two or three vendors. This means manufacturers can often negotiate more favorable terms, and because buyers aren't particularly price sensitive, slot makers have considerable pricing power. On top of that, the licensing and research & development expenditures create formidable barriers to entry to competitors.

What's more, gaming has gone mainstream, and cash-strapped jurisdictions across the country have turned to slot machines (either in casinos, slot parlors, or racetracks) as a new source of tax revenues. There are many of these cities and towns in the U.S., and they are a huge source of new revenues for slot machine manufacturers.

Based on all of this, you would think that investing in any old slot machine manufacturer is a no-brainer, but that's not the case. StreetAuthority's Nathan Slaughter has studied the slot machine business extensively for StreetAuthority's premium value investing newsletter, Half-Priced Stocks, and he's discovered two manufacturers that are expected to receive the bulk of the industry's growth. This includes one company that supplies three out of every four slot machines in North America, yet still trades well below its fair value. But to read Nathan's in-depth analysis of the industry and his two favorite slot machine manufacturers, you need to be a Half-Priced Stocks subscriber. Follow this link to learn more.