Concept:
Classification questions require identifying a common characteristic shared by most items and finding the "odd one out."
Step 1: Analyzing the first three terms.
Habeas Corpus, Mandamus, and Certiorari are all
Constitutional Writs.
These are formal written orders issued by the Supreme Court (Art 32) or High Courts (Art 226).
They are judicial remedies used to protect the fundamental rights of citizens against the state or lower authorities.
Step 2: Identifying the odd term.
An
Affidavit is a written statement confirmed by oath or affirmation.
It is a document used as evidence in court, but it is
not a Writ.
While the others are "Orders" issued by the Court, an affidavit is a "Statement" filed by a person. Hence, Affidavit is the odd one out.