What is the fourth stage in a well-established model of team development that consists of...

The Tuckman model of team development includes five key stages: Forming, Storming, Norming, Performing, and Adjourning​.

Option D (Performing) is correct because it represents the phase where teams work efficiently and effectively toward goals.

Option A (Adjourning) is the final stage, not the fourth.

Options B (Completing) and C (Reporting) are not part of the official Tuckman model.

At the Performing stage, teams function independently, solve problems efficiently, and maintain high productivity​.