AYUDA POR FAVOR ALGUIEN SABE DE ESTO

Okay so i'm taking an online spanish course (penn foster), and in the study guide, you have to create a bunch of sentences with words you've learned so far. translating, reading, and those kinds of things are fairly easy, but when it comes to making my own sentences, my brain just kinda waltz's away. anyone got any tips?

The coexistence of several nationalities within a larger state is known as?

Diego __ de los estados unidos pero ahora en españa. a. está, es b. es, está c. soy, es d. estoy, está