Pilar's best friend calls her about an issue she is having at work, and they speak for about twenty minutes. the next day, pilar's friend asks her a specific question, but pilar has no idea what she is talking about. though pilar swears to her angry friend that she heard her, pilar has discovered what myth about listening?

The correct answer is hearing is the same as listening.
This is a myth about listening - the fact that if you hear something, it automatically means that you understood and remembered what the other person told you, which is obviously not true. In order to really hear something, you need to listen to that person attentively, and show them that you are indeed listening to them.