Jus Sanguinis is a principle that grants citizenship based on

Step 1: Analyze the question The question asks what basis "Jus Sanguinis" uses to grant citizenship.

Step 2: Explain the concept Jus Sanguinis is Latin for "right of blood." Under this principle, a person's citizenship is determined by the citizenship of their parents (or at least one parent), no matter where in the world the person is born.

Compare it with related terms:

• Jus Soli ("right of the soil"): citizenship by place of birth.
• Naturalization: citizenship acquired through residency, usually after a set number of years, and meeting other legal requirements.
• Jus Sanguinis: citizenship by descent, from parents.

Step 3: Work through the options

• A. Parental citizenship: Correct. This is descent, or "blood" ties, in the legal sense of having citizen parents.
• B. Place of birth: This is Jus Soli, not Jus Sanguinis.
• C. Ethnic background: This is a common trap. "Blood" may suggest ethnicity, but the legal test is the parents' citizenship, not their ethnic group.
• D. Length of residency: This is naturalization.

Step 4: Nigerian context Section 25 of the 1999 Constitution of the Federal Republic of Nigeria provides for citizenship by birth. A person born in or outside Nigeria is a citizen if either of their parents or grandparents is a Nigerian citizen. This is Jus Sanguinis in practice.

Answer: A. parental citizenship

Exam tip: Remember it this way: Sanguinis = Same blood as parents. Soli = Soil, the place of birth. When you see "blood," think of parents. When you see "soil," think of the place of birth.