The mass number is the sum of the protons and neutrons in an atom. 235-92 = 143 neutrons. Element 92 is Uranium.
Uranium is also the highest atomic number element which exists in nature. All of the rest above element 92 only exist nuclear high-energy reactions (the transuranium elements), and most experience nuclear decay very quickly and form other elements with fewer protons.
This is called Nuclear fusion Example is two hydrogen atoms fuse to form a helium atom Where some of the atoms of hydrogen turn in to energy So the answer is A
