I believe the answer is C
IMixing combined with skip voting
Separation of components of crude oil
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.
