Answer:
24)
The items in the list are:
Los patines (Skates)
La pelota (The ball)
La pasta dental (The toothpaste)
El palo de golf (The golf club)
Now you can see that 3 of the options are related to an sport, and one, "Pasta dental" is related to healtcare, so this one is the option that does not belong with the other 3.
25)
"Compro la gasolina en la estación de servicio" can be translated to
"I buy the gasoline in the service station"
We want to substitute "la gasilina" with an object pronoun, we can use, in this case, "La"
And we can write the sentence as:
"La compro en la estación de servicio"