The correct answer is: c) Thorium.
Monazite is a rare earth phosphate mineral with the chemical formula (Ce,La,Th,Nd,Y)PO4. It is a common accessory mineral in igneous rocks and is also found in placer deposits. Monazite is an important source of thorium, a radioactive element that is used in nuclear power plants. It is also a source of rare earth elements, which are used in a variety of applications, including electronics, magnets, and batteries.
Iron is a metal that is found in the Earth’s crust. It is the most abundant metal in the Earth’s crust and is the fourth most abundant element in the universe. Iron is used in a variety of applications, including construction, transportation, and manufacturing.
Manganese is a metal that is found in the Earth’s crust. It is the 12th most abundant element in the Earth’s crust and is the ninth most abundant metal in the Earth’s crust. Manganese is used in a variety of applications, including steelmaking, batteries, and fertilizers.
Uranium is a radioactive metal that is found in the Earth’s crust. It is the 92nd element in the periodic table and is the heaviest naturally occurring element. Uranium is used in nuclear power plants and nuclear weapons.