Which bearing receives air from the 9th stage in a gas turbine engine?

The 7B bearing in a gas turbine engine receives air from the 9th stage. In a typical configuration, the bearings in a gas turbine engine are supplied with air to provide cooling and lubrication, which is essential for maintaining operational efficiency and preventing overheating. The 9th stage, being relatively high-pressure air, is routed to the 7B bearing to ensure it operates effectively under the demanding conditions of a gas turbine.

This specific arrangement is critical as it helps manage temperatures and provides necessary lubrication for the bearing's operation. Proper cooling and lubrication not only extend the life of the bearing but also enhance overall engine performance. Other bearings listed do not receive their airflow from the 9th stage, which limits their connection to the cooling and lubrication system established for the 7B bearing. Thus, the 7B bearing's design and its role in the airflow system make it the correct answer.