What is the maximum speed for operating the CRJ 200 elevator trim?

The maximum speed for operating the CRJ 200 elevator trim is correctly identified as 170 KIAS. This limitation is crucial as exceeding this speed could lead to control issues with the aircraft's elevator system. The elevator trim is designed to assist pilots in maintaining control of the aircraft without excessive control inputs, particularly during critical phases of flight like takeoff and landing.

Operating outside of these limitations might not only render the trim ineffective but could also risk damage to the trim system itself or affect the aircraft's stability and maneuverability. Each specific speed reference in the other options reflects parameters for different systems or configurations within the aircraft but is not applicable to the elevator trim operation. Therefore, the established limitation of 170 KIAS is essential for safe and proper handling of the CRJ 200.