Which command circles a specified area in AutoCAD?

The command that circles a specified area in AutoCAD is the CIRCLE command. This command is specifically designed for creating a circle by defining its center point and radius or diameter. When you invoke this command, you can simply click to specify the center of the circle and then either drag out to set the radius or input a numerical value.

The other options do not serve the same purpose. The SPHERE command is used to create three-dimensional spheres rather than flat circles, which does not meet the requirement for circling a specified area in the 2D plane. The ELLIPSE command allows for the creation of ellipses, which are elongated circles and are not appropriate when specifically needing a circle. The term "BASTRO" does not correspond to any known AutoCAD command and is likely a distractor. Thus, the CIRCLE command is the accurate choice for creating a circular area in AutoCAD.