This question asks which Roman law category is philosophically closest to what we today call the Rule of Law, the idea that governance rests on binding, rational, and universal legal principles rather than the arbitrary will of a ruler. Each option represents a distinct branch of Roman legal thought, and examining them one by one shows why only one truly matches this idea.
Only Jus Naturale supplies the idea of a universal, reason-based standard of justice that stands above and constrains human enactments, which is the essence of the Rule of Law.
Hence, the correct answer is Jus Naturale.