Which option describes ads displayed on a rotation in all non-custom ad spaces?

Run of Site (ROS) refers to ads that are displayed on a rotation across all available ad spaces on a site, rather than being limited to specific locations. This approach allows advertisers to reach a wider audience by airing their ads on various pages throughout the site, maintaining a presence without the constraints of designated placements. ROS is effective for general brand awareness and can lead to impressions across different types of content.

In contrast, Roadblock (Takeover) involves occupying all ad spaces on a page simultaneously, creating a more immersive and exclusive advertising experience but not necessarily rotating across the entire site. Psycho-graphic Targeting and Demographic Targeting are strategies focusing on specific audience characteristics rather than the format and rotation of ad placements, making them unrelated to the concept of ads shown on a rotation in all non-custom ad spaces.