Final answer:
The Selection Tool in Illustrator is used to select all of an object. It is represented by a black arrow and you can also select multiple objects by clicking and dragging or holding Shift to add to your selection.
Step-by-step explanation:
The Illustrator tool that can be used to select all of an object is the Selection Tool. The Selection Tool (often represented by a black arrow icon or shortcut key 'V') allows you to click on an object to select the entire object. If you want to select multiple objects, you can click and drag around the objects, or hold Shift and click on additional objects to add them to your selection.
Other tools mentioned serve different purposes: the Direct Selection Tool allows for the manipulation of individual anchor points or paths, the Group Selection Tool allows selecting objects within a group, and the Magic Wand Tool selects objects based on similarity in fill color, stroke weight, opacity, etc.