Which of the following tailwind components is acceptable for takeoff?

For the CRJ 900, acceptable tailwind components for takeoff are typically limited to a maximum of 10 knots. This limitation is important because excessive tailwind can adversely affect the aircraft's performance during takeoff, particularly in terms of distance required to reach takeoff speed and the ability to climb after takeoff.

A tailwind component of 10 knots is therefore within the acceptable range, allowing for safe takeoff conditions while still maintaining necessary performance margins. Allowable takeoff limits ensure that pilots can make informed decisions regarding runway length, weight, and environmental conditions, contributing to overall safety during flight operations.

In contrast, the other options represent tailwind components that exceed the established limitations, which could compromise safety and performance during takeoff.