To address the problem of acid rain and acid deposition, it is crucial to understand the main causes of this environmental issue. Acid rain is primarily caused by emissions of sulfur dioxide (SO₂) and nitrogen oxides (NOx) from burning fossil fuels. These compounds react with water vapor and other chemicals in the atmosphere to form sulfuric acid and nitric acid, which then fall to the ground as acid rain.

The most effective method to reduce acid rain is to target the source of these pollutants. Therefore, let's evaluate the provided options:

1. Adding lime to the acidic lakes: This method, known as liming, temporarily neutralizes the acidity in lakes and waterways. However, it does not address the root cause of acid rain, as it is just a treatment for the effects, not the source.
2. Promotion of acid-resistant crops: This is a measure to mitigate the damage caused by acid rain, not a solution to reduce it. It focuses on adapting to the problem rather than solving it.
3. Increasing the height of smokestacks: While this might disperse pollutants over a larger area, it does not reduce the amount of pollution released. In fact, it may spread the problem over wider regions.
4. Reducing the use of fossil fuels: This directly addresses the main cause of acid rain. By cutting down on fossil fuel use, we can significantly decrease the emissions of sulfur dioxide and nitrogen oxides.

Conclusion: The most appropriate method to reduce acid rain is reducing the use of fossil fuels since it directly tackles the root cause of SO₂ and NOx emissions. This can be achieved by transitioning to alternative energy sources, such as wind, solar, and hydropower, improving energy efficiency, and implementing cleaner technologies.