Cell walls contain peptidoglycan.
a. archaea
b. bacteria
c. both archaea and bacteria

Option B

Explanation:

Peptidoglycan is a polymer that made of amino acids and sugar. This forms a layer of mesh like structure which is found on the outer side of the plasma membrane.

This is found in most of the bacteria which forms the cell wall. The sugar component  that contains the alternating residues of N-acetylglucosamine and N-acetyl muramic acid.

Thus, the correct answer is option B