Mountains are one of the most affected by weathering.
The light that makes up the image of the fish is refracted when it leaves the water and enters the air. Your brain thinks the light traveled straight, so the fish is not located in the direction from you that your brain thinks it is.
Answer is choice #3: Mechanical energy
From equations of motion;
v = u + at, where v = final velocity, u = initial velocity, a = acceleration, t = time taken to reach the final velocity.
Using the values given,
7 = 3 + 0.8*t=> 7-3 = 0.8t
4 = 0.8t
t = 4/0.8 = 5 seconds