Correct answer: B. Equality of law
Explanation: Direct answer: Option B, equality of law. Rule of law requires the law to be applied impartially, whether a person belongs to the ruling party, opposition, rich group or poor group. The reasoning is: applying strict law only to opponents is selective enforcement; selective enforcement is unequal treatment; unequal treatment weakens equality before law and public trust. Option B is correct because the exact principle damaged is equality of law. Option A, date of election, concerns the election schedule and is not automatically changed by biased enforcement. Option C, voter list, concerns registration of eligible voters and is not the direct principle described. Option D, colour of ballot, is merely a physical feature and has no connection with equal legal treatment. The government may investigate or prosecute wrongdoing, but it must use the same lawful standards for its own side and its opponents, with evidence and fair procedure. Memory cue: ‘same offence, same legal standard’, regardless of political side.