What are prepositions

Prepositions indicate direction, time, location, and spatial relationships, as well as other abstract types of relationships.

Prepositions indicate relationships between other words in a sentence.

Many prepositions tell you where something is or when something happened.

As the name suggests they generally tell position if something. Like, behind, front, on, at etc.

the best asnwer is b "les encantan los juguetes nuevos" because you are talking about them

caminas makes the most sense here since it means to walk.