Hola Inma, I have been trying to work out why both direct and indirect objects are present here.
I can't find a reference for a pronominal form of pensar, but on doing the exercise a second time, I noticed that the lesson for the se aspectual was listed as being relevant. Poder isn't given as one of the verbs that typically can take this construction, but does this explain why the reflexive pronoun is being used here, making the verb poder more "intense / complete" as explained in the example of "irse" in the lesson; .... or is there another explanation altogether. Espero que puedas ayudarme. Saludos. John