The correct answer is option 4: "Old Men and Women". PM-2.5 refers to particulate matter that is 2.5 micrometers or smaller in size. These particles can be harmful when inhaled as they can penetrate deep into the respiratory system. Old men and women, especially those with pre-existing respiratory conditions, are more vulnerable to the adverse effects of PM-2.5 pollution. It can worsen respiratory symptoms, trigger asthma attacks, and increase the risk of respiratory infections. Archaeological monuments, national parks, and botanical gardens are not directly affected by PM-2.5 pollution as they are not living organisms. However, it is worth noting that air pollution, including PM-2.5, can have indirect effects on the environment, such as causing damage to buildings or affecting the vegetation in these areas.