Answer: The correct answer is molecule.
Explanation:
Molecule is defined group of two or more atoms of same or different bonded together with the means of chemical bonds.These chemical bonds formed by the sharing and exchanging of electrons between these atom.
Element is the purest chemical substance which consist of similar kinds of atoms.
Ionic bonds are the type chemical bond in which complete transfer of an electrons from one atom to an other occurs.
Hydrogen bonding is type of bonding which occurs due to presence of hydrogen and electronegative atom (Fluorine,oxygen,nitrogen).
Hence,from the given options the correct answer is molecules.