Which button allows one engine to be supplied from an alternate tank group?

The option that allows one engine to be supplied from an alternate tank group is the X-BP 1-2 button. This button is part of the cross feed system and is specifically designed for managing fuel supply to the engines from different tank groups, ensuring that if an engine requires fuel from an alternate source, it can efficiently draw from the designated alternate tank.

In the context of the Dassault Falcon 7X, managing fuel distribution is crucial for maintaining balance and ensuring that each engine operates smoothly without interruption. The functionality of the X-BP button facilitates this by allowing pilots to control the fuel flow and make adjustments as needed.

Other options relate to different aspects of engine and fuel management. For example, the "ENG 1 Start" option is focused on initiating engine start procedures rather than managing fuel supply. "Fuel Transfer" pertains to moving fuel between tanks but does not directly allow for engine supply from alternate tank groups. Similarly, "Tank Select" allows the pilot to choose which tank to draw fuel from but does not specifically indicate the capability to supply an engine from an alternate tank group in the same manner as the X-BP button does.