Answer: 25 km
Explanation: If it travels 25 km in 1 hour it is going 25 km/h meaning if its speed doesn't change for the next hour it will go another 25 km.
The thermal efficiency of an engine is

where
W is the work done by the engine
Q is the heat absorbed by the engine to do the work
In this problem, the work done by the engine is W=200 J, while the heat exhausted is Q=600 J, so the efficiency of the machine is
The answer is C) an electromagnetic wave
An electromagnetic wave, which includes electromagnetic radiation such as visible light, moves the fastest of all of the options listed by a significant margin, especially through space. In fact, light travelling through space is technically the theoretical limit of how fast something can travel.