Answer: The correct answer is Option C.
Step-by-step explanation:
A covalent bond is defined as the bond which is formed when sharing of electrons takes place between the atoms forming a compound. This type of bond is usually formed between two non-metals.
From the given options:
Option A: two gold atoms
Gold atom is a metal and thus, will not form covalent bond.
Option B: two neon atoms
Neon atom is a noble gas and is unreactive atom. Thus, it will not form covalent bond.
Option C: hydrogen and oxygen atoms
Both the atoms are non-metals and thus, will lead to the formation of a covalent bond.
Option D: magnesium and bromine atom
Magnesium atom is a metal and bromine atom is a non-metal. Thus, they will not lead to the formation of covalent bond but will form ionic bond.
Hence, the correct answer is Option C.