Which of these sentences is a command

Hola, susana. pablo. ¿qué tal? answer for blank 1:

Which one of the following is the correct rhyme to keep in mind when using the spanish counterparts to this, that, those and these? a: “that” and “those” both have s’s, “this” and “these” don’t b: “that” and “those” both have t’s, “this” and “these” don’t c: “this” and “these” both have s’s, “that” and “those” don’t d: “this” and “these” both have t’s, “that” and “those” don’t

No debemos el medio ambiente. a. contaminar b. preservar c. desechar d. cumplir