The correct answer is - C. a king or queen is the head of state, but Parliament makes the laws.
The United Kingdom officially goes as a country that is a constitutional monarchy. This means that the head of the state is a king or a queen. In practice though, the monarch doesn't really has any particular political power but it is more of a symbolic and traditional thing. The king or queen have their title by the law of inheritance, thus the monarch is from the family.
In practice, the British society is a parliamentary democracy. There's a multiparty system when the people are free to choose their leaders on elections.