Answer:
The kingdoms united for protection against attacking invaders.
The concept of risk behaviour refers to a lifestyle/actions that placed people at a certain negative risk in order to get a certain positive reward.
For example, some people ill try to mount climbing on an extreme terrain in order to get an adrenaline rush. Another example would be someone who opened up a new business by risking the loss of his/her entire fortune.
The answer is C, this is why the Supreme Court hears cases, to determine their constitutionality.
