Here as we know that there is no loss of energy
so we can say that maximum kinetic energy will become gravitational potential energy at its maximum height
So here we have

here we have
v = 20 m/s
m = 8000 kg
now from above equation we have



so maximum height is 20.4 m
I believe there are two correct answers, and those answers are A and D
The width is 2.5 cm long and could not be the right answer
It increases as the number of protons and electrons in the shell increases