You need to create a relationship between two tables. The Account table stores information about the companies that supply equipment to your company, such as Account Name (name of the company), main phone, city, primary contact, primary email, and status. Your custom table Equipment stores the details about the equipment that these companies supply, like equipment name, equipment type, price, etc. 
What type of relationship will you create between Equipment and Account tables?

Answer options:

A.One-to-One (1:1)
B.One-to-Many (1:N)
C.Many-to-One (N:1)
D.Many-to-Many (N:N)

Correct Answer: C 
Dataverse defines the two types of relationships between tables: One-to-Many (1:N) and Many-to-Many (N:N). 
A One-to-Many relationship is a Parent-Child relationship, like between a company and multiple products that it supplies. One company can sell various types of equipment. The company record in the Account table is related to the multiple records in the Equipment table. It is a One-to-Many relationship for a company record. For the related equipment record, this relation is Many-to-One (Number 1). 
When you create such a relationship between tables, the Dataverse automatically adds a Lookup column (Number 2) in a child or related table (Equipment). When you relate two tables in the Many-to-One or One-to-Many relationship, you need to instruct the Dataverse what to do when you delete the records from the parent table (Number 3). 

Option A is incorrect because Dataverse does not support the One-to-One (1:1) relationship between tables. It provides only One-to-Many (1:N), Many-to-One (N:1), and Many-to-Many (N:N).
Option B is incorrect because, from the Equipment table side, the relationship is Many-to-One (N:1). One-to-Many (1:N) relationship is from the Account side.
Option D is incorrect because the Equipment and Account tables` relationship is Many-to-One (N:1) but not Many-to-Many (N:N).
For more information about the Dataverse types of table relationship, please visit the below URLs: 

https://docs.microsoft.com/en-us/powerapps/maker/data-platform/data-platform-entity-lookup
https://docs.microsoft.com/en-us/powerapps/maker/data-platform/create-edit-entity-relationships