When Vaseline is applied to both surfaces of the leaves of a plant, it forms a thick barrier that prevents the exchange of gases and the loss of water through the leaf surface.

1. Photosynthesis: Photosynthesis is the process by which plants convert sunlight, carbon dioxide, and water into glucose and oxygen. The application of Vaseline would hinder the intake of carbon dioxide and the release of oxygen, affecting the process of photosynthesis.

2. Respiration: Respiration in plants is the process by which they utilize glucose and oxygen to produce energy, carbon dioxide, and water. The Vaseline barrier would limit the intake of oxygen and the release of carbon dioxide, inhibiting respiration.

3. Transpiration: Transpiration is the process by which water is lost from the leaves through tiny openings called stomata. Vaseline blocks the stomata, reducing the ability of the plant to transpire and lose water.

In conclusion, the application of Vaseline to both surfaces of the leaves of a plant would affect all three processes mentioned in the options: photosynthesis, respiration, and transpiration. Therefore, the correct answer is 4.