Çözüldü Newton's Law of Universal Gravitation - Conservation of Mechanical Energy

Assuming the moon has mass M and radius R with the Universal Gravitational Constant G, if a small object is dropped from a distance of 3R from the moon’s center, which of the following values equals k if the object’s impact speed when it strikes the surface of the moon is (k·G·M / R)^0.5 ?

A) 1 / 3
B) 2 / 3
C) 3 / 4
D) 4 / 3
E) 3 / 2


https://i.ibb.co/61pLb7V/Newton.png
https://www.cracksat.net/sat2/physics/question-34-answer-and-explanation.html

Notes:
f: Final
U: Potential Energy
K: Kinetic Energy
The problem's original wording has been slightly changed.