To use the 3 sketched cross sections (2 rectangles and a circle) to create the solid body as shown, use the _______ command.

The Loft command is the appropriate choice for creating a solid body from multiple sketched cross sections, especially when those cross sections are different in shape or size, such as in the case of two rectangles and a circle. Lofting allows for smooth transitions between these profiles, creating a solid that connects them in a 3D space. This is particularly useful when the geometries do not share a common profile but need to be integrated into a continuous form, showcasing the ability to generate complex shapes that align with the specified cross sections.

In contrast, the other commands serve different purposes: the Revolve command is primarily used for creating solids by rotating a profile around an axis, which works well for symmetrical shapes like cylinders. The Extrude command extends a 2D shape along a straight line to create a solid, typically useful for uniform thickness scenarios, while the Sweep command follows a defined path with a profile, generating solids along a specified trajectory. Each of these alternatives has its specific application, but they do not effectively combine multiple diverse profiles in the manner that the Loft command does.