The outside of electrical wires often have a layer of insulation to protect the user from being shocked. This protective layer is often made from

Most electrical wire is covered in a rubber or plastic coating called insulation.

Explanation:

Wires used in homes are usually covered with materials like plastic or rubber, because plastic and rubber are bad conductors of electricity and do not allow current to flow. This prevents us from getting a shock due to a short circuit.

alkaline metals are lithium, sodium, rubidium, potassium, cesium and francium.

alkali metals have electronegativity from 0.7 to 1, lowest in periodic table of elements, which means that alkali metals (i group in periodic table) has positive oxidation number in compounds.

electronegativity is a chemical property that describes the tendency of an atom to attract a shared pair of electrons towards itself.

alkaline metals (far left in main group) have lowest ionizations energy and easy remove valence electrons,

for example, potassium is the alkali metal and has a single valence electron in the outer electron shell.

electron configuration of potassium is: ₁₉k 1s²2s²2p⁶3s²3p⁶4s¹.

they can not exist alone in nature, because they are very reactive.

i think it's c. i'm not sure but i think so.