Note: I'm not sure what do you mean by "weight 0.05 kg/L". I assume it means the mass per unit of length, so it should be "0.05 kg/m".
Solution:
The fundamental frequency in a standing wave is given by

where L is the length of the string, T the tension and m its mass. If we plug the data of the problem into the equation, we find

The wavelength of the standing wave is instead twice the length of the string:

So the speed of the wave is

And the time the pulse takes to reach the shop is the distance covered divided by the speed:
The kinetic energy is given by:

We know the mass and the maximum speed, plugging their values in the expression above we have:

Therefore, the answer is d.
Answer:
The answer to your question is C
Explanation:
acceleration is a vector quantity because it has both magnitude and direction