Correct answer: B. Equality before law
Explanation: The direct answer is B, equality before law. In a lawful democracy, police must apply the law fairly to powerful and weak people alike. Step by step: police have a duty to enforce law; they enforce it only against weak people; powerful people are unfairly spared; therefore the same law is not being applied equally. Option B is correct because equality before law requires equal treatment and rejects selective enforcement. Option A, regular elections, concerns how representatives are chosen and is not the direct issue in this situation. Option C, secret ballot, protects the privacy of a voter's choice and has nothing to do with unequal police action. Option D, electoral competition, concerns parties or candidates competing for votes, not fair law enforcement. Selective enforcement can also harm justice and rights, but among the given options the precise principle is equality before law. Memory cue: if identical wrongdoing receives different treatment because of power, think equality before law.