Advances in refrigeration in the late 1800s had a significant impact on Washington and its agricultural economy. The most notable effect was that food could be transported and stored more efficiently. With improved refrigeration techniques, perishable goods such as fruits, vegetables, and meats could be preserved for longer periods, reducing waste and allowing farmers to transport their products over longer distances without spoilage.
This advancement opened up new markets for Washington's agricultural products, enabling local farmers to sell their crops not only in their immediate area but also in distant markets. The ability to keep food fresh also meant that consumers had access to a wider variety of products throughout the year.
In summary, while some of the other options may hold some truth, the primary impact of refrigeration advancements was the enhanced efficiency in food transportation and storage.