What is the difference between a Buyer Agent, Dual Agent and Exclusive Buyer Agent?

Buyer Agent
A real estate agent that works in a company that takes listings and represents buyers under a contract
If the Buyer decides that he wants to buy one of the properties listed with the company this would cause a conflict and the agent would be a dual agent this is illegal unless it is Disclosed.

Disclosed Dual Agent
The agent would have to disclose in writing to both parties, sign that they represent the buyer & seller in the same transaction
If the seller refuses, in RI the agent would have to DROP the Buyer and represent the Seller, but still treat the buyer honestly and fairly

Exclusive Buyer Agent
An Agent that works in an office that takes no listings and only works for Buyers 100% of the time!