c. Outline View

Outline view shows your thoughts in a more traditional outline. To activate this view choose View > Outline.

Outline view behavior differs from Normal view in quite a few ways:

First, you can expand and collapse thoughts while not changing the active thought. To do this, hover over a thought and click the + or - button that appears. 

Changing the active thought will still center that thought. However for you can still view parents and grandparents and grandparent parents etc. for thoughts higher in the hierarchy. For items lower in the hierarchy you can expand them so you can view all their children, and children's children. For this reason it's usually more effective to use hierarchy view by activating the top thought and then manually expanding the thoughts below to view the structure. You can also use cmd (or ctrl ) and the plus sign to expand a hierarchical level at a time, and cmd/ctrl  and the minus sign to collapse a level at a time. 

Showing the notes window by right clicking any thought and choosing Show Notes Window is very useful in this view.

You can also adjust where the thoughts are in outline view by clicking and dragging the plex (not the thoughts) or scrolling while not mousing over a thought.

I use this view when I have data that fits into a hierarchical structure well. For example, lists, procedures, folder structure or date representations.