The correct option is A Chrysophytes
Chrysophytes include diatoms and desmids. They have cell walls impregnated with silica, which makes the walls indestructible. Their cell wall deposits are called 'diatomaceous earth'.
Euglenoids are Euglena-like protists which do not have cell walls.
Protozoans are animal-like protists, which do not have cell walls either.
Slime molds are fungi-like protists, which have cell walls that decompose over time.