I believe the correct answer would be C. Sartorius i believe this is the answer, after doing some research on gO0gLe.
Answer:
Nuclear energy because it can never be reused again
Given that,
The speed of a wave, v = 200 m/s
Wavelength, 
We need to find the frequency of this wave. The relation between wavelength, frequency and the speed is given by :

So, the frequency of this wave is 100 Hz.