Reasoning

All others can be drawn on paper.

A circle, oval, and sphere are all circular shapes with no angles. A triangle is a different kind of shape with angles and three straight sides.

All except Cliffs are structures formed by underground water, while cliffs are formed by sea.

Defendant, prosecutor, and judge are all persons involved in a trial. A trial is not a person.

All except Shovel are tools used for cutting or chopping.

All except Ellora are famous for temples, while Ellora is famous for caves.

All except Poet perform on stage.