Final answer:
Politics is the process of gaining or maintaining control over government for reaching common action and involves the distribution of power within a society. An oligarchy is a government held by a small elite group, not described in the initially provided options. Bureaucracy is essential for managing large groups efficiently, but distinct from the concept of politics.
Step-by-step explanation:
The process of people gaining or maintaining control over the government in order to reach an agreement on a course of common action is known as politics. This involves the struggle for power and the establishment of rules that govern a particular space, whether it be a local community or the entire globe. Politics decides 'who gets what, when, and how' in a society, defining how power is distributed and exercised.
A form of government where a small group of elite people hold political power is called an oligarchy, which is different from the options provided. Meanwhile, in a democracy, characteristics include the election of officials through voting, protection of citizens' basic rights, and operation based on a constitution. This is contrary to a system where a king or queen holds the majority of governmental power, which is not characteristic of a democracy.
A bureaucracy, on the other hand, is a system designed to manage large groups of people efficiently through a set of rules, records, and a chain of command, and is essential in large political units. It is not primarily concerned with the process of people reaching an agreement on courses of action, which is the realm of politics. Diplomacy involves managing international relations and is also distinct from the internal governance processes of politics.