What does a hydrogen bond mean

It is a weak form of electrostatic attraction between an hydrogen atom and another electronegative atom like fluroine or oxygen

Explanation:

Hydrogen bond is the a weak non-covalent formed between molecules. They can be easily broken by using the appropriate amount of force. This type of bond can be formed between two separate molecules or in between molecules, i.e intermolecular forces.

Hydrogen bond is stronger than Van der waals force of attraction but they are however weaker than iconic bonds and covalent bonds. Hydrogen bonds play a vital role in biochemistry and it is also responsible for many different characteristics properties of water.

if you mean hydrogen and oxygen then water is the product

the answer is b. dilution