Right answer
b. aconsejo
Al tomar un taxi, te aconsejo que preguntes por los precios
In this sentence, the indirect object pronoun for the second person singular (te) is being used. An Indirect Object Pronoun is a person that receives the action of a verb indirectly. Its purpose is to tell you to whom or for whom something is done. Here the action is being performed for you, so aconsejo is the conjugation of the verb aconsejar for the first person singular matching this indirect object pronoun.
