Answer: Option 3.
Explanation:
Formula for kinetic energy is
K.E = (1 / 2) * (m * v ^ 2)
Assuming mass to be constant,
We can see that K.E is proportional to v^2.
It means that when you substitute the value of velocity in v, kinetic energy increases with v^2.
Option 1 and 2 are eliminated because the relationship between kinetic energy and velocity in the graph is shown as linear. We already know from formula that the relationship is not linear.
Option 4 is incorrect because kinetic energy must be zero when velocity is zero. This graph shows kinetic energy is becoming infinite as velocity tends to 0.
So option 3 is correct answer.
B) The amount of work done
I think it's longitudinal wave because the particles move parallel to the direction that the wave is traveling.
Answer:

Explanation:
Here we know that for the given system of charge we have no loss of energy as there is no friction force on it
So we will have


now we know when particle will reach the closest distance then due to electrostatic repulsion the speed will become zero.
So we have



so distance moved by the particle is given as


