The correct answer will be option-gravitational energy.
Explanation:
The gravitational force is the attractive force which exists between two objects with mass. This attractive force directly influence the other object as it helps maintain the object in the universe.
When one of the objects out of two is earth, the force is termed as gravity or it is the force with which the earth attracts the object.
The gravity is directly proportional to mass due to which the earth will attract the object with stronger force. When the object will be present at the height the strongest force applied on the object will be the gravitational force.
In alpha decay, the daughter nucleus is two units less than the parent in atomic number. The mass number also decreases by 4 units. The daughter is thus found two places before the parent in the periodic table.
