Final answer:
Otto was named the first King of modern Greece in 1832 after the Greek War of Independence, establishing the new monarchy.
Step-by-step explanation:
In 1832, Otto became the first King of the modern Greek state, making option B the correct answer. His reign followed a significant period in Greek history that included the Greek War of Independence against Ottoman rule. Otto, the second son of King Ludwig I of Bavaria, was chosen by the Great Powers (Britain, France, and Russia) to rule the new Kingdom of Greece as a constitutional monarch. The choice of a Bavarian prince came as Greece was looking for a way to establish a stable and recognized monarchy after the struggle for independence.