What are the four main 'Temperament' types called within David Keirsey's Temperaments personality theory?

As explained by Mr. Vinod Jetley. Expert answer.

The Four Temperaments

• As Concrete Cooperators, Guardians speak mostly of their duties and responsibilities, of what they can keep an eye on and take good care of, and they're careful to obey the laws, follow the rules, and respect the rights of others.
• As Abstract Cooperators, Idealists speak mostly of what they hope for and imagine might be possible for people, and they want to act in good conscience, always trying to reach their goals without compromising their personal code of ethics.
• As Concrete Utilitarians, Artisans speak mostly about what they see right in front of them, about what they can get their hands on, and they will do whatever works, whatever gives them a quick, effective payoff, even if they have to bend the rules.
• As Abstract Utilitarians, Rationals speak mostly of what new problems intrigue them and what new solutions they envision, and always pragmatic, they act as efficiently as possible to achieve their objectives, ignoring arbitrary rules and conventions if need be.