DRAG DROP
A company is creating a new system based on Common Data Service. You need to select the features that meet the company’s requirements.
Which options should you use? To answer, drag the appropriate options to the correct requirements. Each
option may be used once, more than once, or not at all. You may need to drag the split bar between panes or scroll to view content. NOTE: Each correct selection is worth one point.
Answer: 
Explanation:
Box 1: self-referential relationship
Box 2: connection
There are other less formal kinds of relationships between records that are called connections. For example, it may be useful to know if two contacts are married, or perhaps they are friends outside of work, or perhaps a contact used to work for another account. Most businesses won’t generate reports using this kind of information or require that it is entered, so it’s probably not worthwhile to create entity relationships.
Box 3: one-to-many relationship
Box 4: many-to-many relationship
Reference:
https://docs.microsoft.com/en-us/powerapps/maker/common-data-service/create-edit-entity-relationships