Which sentence in the passage conveys the message that drones can be used in the study of history?DronesDrones are radio controlled aircrafts that fly without a human pilot onboard. They are also known as unmanned aerial vehicles (UAV). Drones are sometimes controlled by onboard computer systems. They can also be controlled with radio signals sent by humans on the ground or in other aircrafts. Unmanned aircrafts were originally designed for military use. They were initially used as target practice. However, as the technology became more advanced, the military found different ways to use drones. Eventually, UAVs were sent into enemy territory to fly overhead and survey the situation, which kept pilots out of danger. After seeing the successful use of drones in the military, civilian organizations began to employ the use of UAVs. Police departments now use drones to survey crowds during large events. Fire departments use drones to look for people in collapsed buildings. Drones have been used by firefighters to survey and create containment plans while battling wildfires. Search and rescue organizations also use UAVs to help rescue people who are lost in the wilderness or at sea. Private companies use drones as well. Energy companies use the aircraft to survey power lines and oil pipelines. Because these drones typically include cameras to relay pictures or video back to the operator, they save the company time and money. During a recent oil spill, UAVs were used to assess the damage and to check how far the oil had spread. The popularity of drones has grown steadily as the many uses for the aircraft have become clearer. For example, drones were used during the 2014 Winter Olympics in Sochi to film skiing and snowboarding events. The drones allowed cameras to get close to the athletes without the use of the bulky pulley systems normally used at sporting events. Filmmakers have also begun using drones to film scenes in movies. The drones can capture images of large crowds and wide landscapes. Nonprofit organizations have also begun using drones. The World Wildlife Fund (WWF) uses drones to keep track of wildlife populations. Archaeological researchers in Peru and Greece have used UAVs to map ancient sites. This practice helps preserve archaeological sites because it ensures that fewer people will be trampling among the ruins. The possibilities for using drones seem endless. Imagine a world where companies can deliver orders immediately after purchase, or a time when food, water, and medical supplies can be easily transported to communities in rural areas. Drones of the future could make all of that possible.