The correct answer is true.
It is true that there were 1000's of kings in Europe, but three held the most power.
During the history of Europe, there have been many powerful kings and queens that controlled its territories in a successfully. But there were three that were very powerful for the dominion of their lands.
Charlemagne, or Charles the Great -King of the Franks- unified a big portion of Western Europe. Pope Leo III crowned him emperor of the Roman Empire. Louis IV of France was a powerful king and made a great country of France. He even had colonies in America. Queen Elizabeth I of England was a prominent Queen that put emphasis on the economy of the Empire and started the exploration of new territories.