Which of these countries is a kingdom?

Here is the question :

WHICH OF THESE COUNTRIES IS A KINGDOM?

Here is the option for the question :

Belgium
China
Germany
Switzerland

The Answer:

And, the answer for the the question is :

Belgium

Explanation:

[STC002017] The government of the Kingdom of Belgium is a representative democracy, and its monarch is constitutionally ensconced in that role as head of state. This king is Philippe, King of the Belgians, who ascended to the throne in 2013. He has been in power since 2013. He controls the country alongside Sophie Wilmes, who just took office as the brand-new Prime Minister and is the first woman to ever hold that post in the nation.