Many people have long dreamed of being able to fly around as simply as riding a bicycle.  Yet the safety and strength of a flying bike was always a big problem. Over the past 10 years, developments in technology have moved the dream of personal flying vehicles closer to reality. Now, two groups of inventors say such vehicles may be available very soon. Grant Stapleton from Malloy Aeronautics says the Hoverbike, which is able to get in and out of small spaces very quickly, will be a truly personal flying vehicle.  "It can be moved across continents very quickly because it can be folded and packed," he adds. Mr. Stapleton says safety was the company's main concern when developing the Hoverbike. He ays the designers solved the safety issue by using overlapping rotors     to power the vehicle.  The company is testing both a one-third size model and a full-size prototype     of the Hoverbike. Inventors say their Hoverbike will most likely be used first by the police and emergency rescue teams. In New Zealand,  the Martin Aircraft Company is also testing a full-size prototype of its personal flying bike, called Jetpack. It can fly for more than 30 minutes, up t0 1,000 meters high and reach a speed of 74 kilometers per hour. Peter Coker is the CEO of Martin Aircraft Company.  He said Jetpack "is built around safety from the start, " In his words, "reliability is the most important part of it.  We have safety built into the actual structure itself, very similar to a Formula One racing car. " Jetpack uses a gasoline-powered engine that produces two powerful jet streams.  Mr. Coker says it also has a parachute   that can be used should there be an emergency. "It opens at a very low altitude and actually saves both the aircraft and the pilot in an emergency," he adds. Which of the following words can best describe the Hoverbike?
Powerful. Fast. Portable. Available.
Question: Many people have long dreamed of being able to fly around as simply as riding a bicycle.  Yet the safety and strength of a flying bike was always a big problem. Over the past 10 years, developments in technology have moved the dream of personal flying vehicles closer to reality. Now, two groups of inventors say such vehicles may be available very soon. Grant Stapleton from Malloy Aeronautics says the Hoverbike, which is able to get in and out of small spaces very quickly, will be a truly personal flying vehicle.  "It can be moved across continents very quickly because it can be folded and packed," he adds. Mr. Stapleton says safety was the company's main concern when developing the Hoverbike. He ays the designers solved the safety issue by using overlapping rotors     to power the vehicle.  The company is testing both a one-third size model and a full-size prototype     of the Hoverbike. Inventors say their Hoverbike will most likely be used first by the police and emergency rescue teams. In New Zealand,  the Martin Aircraft Company is also testing a full-size prototype of its personal flying bike, called Jetpack. It can fly for more than 30 minutes, up t0 1,000 meters high and reach a speed of 74 kilometers per hour. Peter Coker is the CEO of Martin Aircraft Company.  He said Jetpack "is built around safety from the start, " In his words, "reliability is the most important part of it.  We have safety built into the actual structure itself, very similar to a Formula One racing car. " Jetpack uses a gasoline-powered engine that produces two powerful jet streams.  Mr. Coker says it also has a parachute   that can be used should there be an emergency. "It opens at a very low altitude and actually saves both the aircraft and the pilot in an emergency," he adds. Which of the following words can best describe the Hoverbike?
A. Powerful.
B. Fast.
C. Portable.
D. Available.
Answer: