If the artist likes to create large works and wants to be able to erase, Soft Pastel would be the best choice among the options provided. Soft pastels allow for large applications of color and can be blended easily, and they can be erased or worked on with tools like kneaded erasers to create highlights or soften areas.
In contrast, markers are generally permanent, colored pencils can be difficult to erase entirely, and oil pastels are less forgiving when it comes to erasing.