What major advancement in fire apparatus included a pump capacity of 250 gallons per minute or more?

The major advancement in fire apparatus that includes a pump capacity of 250 gallons per minute or more is the triple-combustion pumper. This type of pumper represents an evolution in firefighting technology, allowing for significantly increased water flow compared to earlier methods. The triple-combustion pumper typically incorporated multiple sources of energy to enhance its pumping capabilities, including internal combustion engines, thereby providing a reliable and powerful source of water during firefighting operations.

While the other options relate to firefighting equipment, they do not feature the same level of pumping capacity or innovation. For instance, a booster tank is designed to store water but does not include a pumping mechanism with such high flow rates. Hand pumps were more common in earlier firefighting history and typically achieve much lower capacities compared to modern pumpers. Chemical wagons are specialized units that carry fire extinguishing chemicals rather than focusing on significant water delivery, making them unsuitable for the question regarding pump capacity.