Microsoft hasn't made a lot of headway with its mobile strategy, but Chief Financial Officer Peter Klein says there is no alternative plan. "It's less 'Plan B' than how you execute on the current plan," he said when asked at an investor conference about options beyond its Surface tablet and Windows Phone pursuits. Klein said Microsoft's Windows 8 platform is perfectly suited for screen sizes from 4 to 13 inches, and he said the company's tablet will help, rather than alienate, its hardware partners because it "allows us to innovate in ways in which we couldn't before."