The correct answer is A) Airplanes.
Airplanes decreased the amount of shipping time and increased the amount of farm and merchant goods that could be shipped.
Due to the use of new technology and cargo machines, the arrival of Airplanes helped to decrease the amount of shipping time. Airplane represented an innovation in cargo. They had a big space for shipment and products such as farm goods and merchant goods of all types and sizes could be transported in a secured way in less time, optimizing the costs of transportation and the frequency of the shipments.