Question

1. how would you say "they want the boots"

Answer 1

1. "They want the boots" = D. quieren las botas. 
Quieren is short for Ellos/Ellas/Ustedes quieren, which means They want. A is incorrect because it refers to You = Vosotros. B is incorrect because it refers to third person singular - He/She/It = El/Ella/Usted. C is incorrect because it refers to We = Nosotros.

2. "Prefiero la gorra roja" = B. I prefer the red cap.
This is becaise Prefiero is short for Yo prefiero, which is the first person singular I.

3. El cadejo is B. a mythical dog. 
It is a supernatural being in Mexican folklore.

4. B. Sawdust is used to make special carpets in Honduras. This process was introduced in 1936.