What feature is used to connect a balloon to a face?

The correct choice identifies that a balloon in SolidWorks is connected to a face using a line. Balloons are commonly used in assemblies and drawings for identifying components, and attaching them with a line provides a clear visual link between the balloon and the corresponding part or assembly feature. This connection helps users quickly see how the balloon references a specific component, ensuring accurate communication of part identification in technical drawings.

The method of using a line allows for flexibility in how balloons are placed; it can accommodate various layouts and maintain clarity of the connection. This practice is especially important in complex assemblies to avoid confusion regarding which balloon corresponds to which part.

In contrast, using a bracket or an arrow would not effectively represent the association between the balloon and the face, as these methods do not provide the same level of clarity or conventional use in technical documentation. The option stating that the balloon is not attached at all also detracts from the standard practices of creating informative drawings, where clear identification is critical.