Concept:Citizenship is acquired through legally recognized procedures of a state.
Explanation:There are several ways by which a person can become a citizen of a country.
The most common methods are by birth and by naturalization.
Birth citizenship can arise from being born within the country's territory or through the nationality of one's parents.
Naturalization is a legal process whereby a foreigner is granted citizenship after meeting certain conditions.
Marriage, registration, and conferment are other possible methods, but they are not the strongest pair given in the options.
Therefore, the best answer is the option that states “Birth and naturalization.”
Answer:C. Birth and naturalization