Concept:A writ is a legal order issued by a court to enforce a right or remedy a wrong.Explanation:The writ of habeas corpus protects individual freedom against unlawful detention.It orders the person detaining another to bring the prisoner before a judge.The judge then checks whether the detention has lawful grounds.If no valid reason is shown, the detained person must be released.The other options are different writs: mandamus, prohibition, and certiorari are used for other legal purposes.Answer:A. Habeas corpus