Answer:
The frequencies are 
Explanation:
From the question we are told that
The speed of the wave is 
The length of vibrating clothesline is 
Generally the fundamental frequency is mathematically represented as

=> 
=> 
Now this other frequencies of vibration experience by the clotheslines are know as harmonics and they are obtained by integer multiple of the fundamental frequency
So
The frequencies are mathematically represented as

=> 
Where n = 1, 2, 3 ....
An hypothesis is a sort of "untested idea" as to what might be happening. I guess it becomes a theory if experiments back it up, and if the combination leads to other things.So, I'd go for The top pair of answers.
Answer:
A, Magnetism
Explanation:
An ordinary electric generator produces electric power by spinning a strong magnet inside a set of wire coils. As the magnet spins, its magnetic field sweeps across the coils and gives rise to electric fields in those coils.
Hope this helps!!
https://www.siyavula.com/read/science/grade-10/sound/10-sound-03