Fitbit the Pedometer Is Getting Kicked Up a Notch with the the New

Fitbit
The pedometer is getting kicked up a notch with the new Fitbit device. The Fitbit is a $99 motion-detecting sensing device that can measure the user's activity even when asleep. It digitally records the distance a user walks or runs, right down to the number of steps, and calories burned. The device wirelessly sends data to its Web site, fitbit.com, giving users minute-by-minute details. Users can add consumption information at the Web site, allowing an accurate picture of calorie consumption and expenditures. Unlike other devices, like the Nike + iPod Sport Kit that monitors walking and running and sells for $29 or the Zeo Personal Sleep Coach that records brainwaves while the user is sleeping and sells for $399, the Fitbit combines both functions. The first-time Fitbit setup isn't very easy for users, but once over that hurdle, it's relative easy to use.
-Refer to Fitbit.The fact that Fitbit can monitor motion while awake and asleep makes it different from competing products that might increase its rate of adoption.Which product characteristic affecting the rate of adoption does this illustrate?

A) Complexity
B) Compatibility
C) Relative advantage
D) Observability
E) Trialability