The correct answer is C. inert gases.
Inert gases, also known as noble gases, are the chemical elements in group 18 of the periodic table. They are all gases at standard temperature and pressure and have very low chemical reactivity. This is because they have a full valence shell of electrons, which makes them very stable. The inert gases are helium, neon, argon, krypton, xenon, and radon.
Bimetallic is a term used to describe two or more metals that are bonded together. The metals are usually chosen for their different properties, such as their strength, corrosion resistance, or electrical conductivity. Bimetallic strips are often used in thermostats and other temperature-sensitive devices.
Transition elements are the chemical elements in groups 3-12 of the periodic table. They are all metals and have a wide range of properties. Transition elements are important in many industrial applications, such as the production of steel and other alloys.
Rare earth elements are a group of 17 elements that are found in the Earth’s crust in very small amounts. They are essential for the production of many modern technologies, such as electronics, batteries, and magnets.