The correct phrase for "These are the rooms" in Spanish is C. Estos son los cuartos.
- A. Estras son las cuartos has a typo ("Estras" should be "Estas" and "las" should be "los" since "cuartos" is masculine).
- B. Este es el cuarto means "This is the room," which is singular.
So, the best choice for "These are the rooms" is C.