Step 1: Constitutional basis.
Articles 13, 32, and 226 provide the textual foundation for courts to review laws/executive actions for consistency with the Constitution.
Step 2: Underlying doctrine.
Judicial review operationalizes the {Rule of Law}—no authority is above the Constitution; arbitrary action must yield to legality and reason.
Step 3: Evaluate options.
Natural justice and democracy are related concepts but not the direct doctrinal basis; ``tradition and cases'' is incomplete absent constitutional supremacy.
Step 4: Conclude.
\[
\boxed{\text{Rule of Law (Option A).}}
\]