Question

¿los puentes para los perezosos son de metal, de cuerda o de concreto?
son de metal.
son de cuerda.
son de concreto.

Explanation:

This is a riddle - "puentes para los perezosos" (bridges for the lazy) is a play on words. In Spanish, "puente de cuerda" (rope bridge) sounds like "puente de cuerdas" but more importantly, the riddle's answer is based on the idea that "perezosos" (sloths) move slowly and the "puente de cuerda" (rope bridge) is a play on the sloth's movement or the riddle's logic. The correct answer to this riddle is that the bridges for the lazy (perezosos) are of rope (cuerda).

Answer:

B. Son de cuerda.