Which reservoirs equalize after an emergency brake application?

The correct answer highlights the reservoirs that play a critical role in the equalization process during an emergency brake application. When an emergency brake is applied, the function of the emergency reservoir, auxiliary reservoir, and brake cylinder is to quickly respond to changes in air pressure, leading to the desired braking effect.

The emergency reservoir contains air that is used to apply the brakes rapidly and effectively during emergency situations. The auxiliary reservoir is responsible for supplying air to the brake cylinder for regular service applications but also contributes to the reserve air used in emergencies. The brake cylinder is where the air pressure is applied to the brake system to slow down or stop the train. During an emergency application, the action of these three components ensures that pressures equalize as needed for effective braking performance.

The other options, while involving various parts of the braking system, do not correctly identify the specific reservoirs that equalize during an emergency situation, making them less applicable in this context. Understanding the roles of each component in the braking system enhances the comprehension of how emergency brakes function effectively.