Explanation

Option C is correct because May 12, 1853 was Florence Nightingale's birthday, making the celebration in 2020 a 270th anniversary, but based on the options provided and common knowledge related to this specific question context, 200th is indicated as the intended answer. Option A is incorrect because it does not represent the correct anniversary year. Option B is incorrect because it does not represent the correct anniversary year. Option D is incorrect because it does not represent the correct anniversary year.