How did you hear about this position?
It always appears to be such an easy question to answer. The Hr manager wants to know which medium has been effective for the company so that they can optimise their costs in any future campaigns. They also get a clearer indication of the type of personaity traits you may have. If for example you heard about it from a friend it shows that you know someone who works for the company, if you read it in a newspaper then you have been actively been researching what is available to you in your sector. Either way you should indicate what interested you about the position.
* I was reading through last weeks edition of the Daily Express and noticed your advert. The fact that you are a recognised brand looking for someone with a background in Client portfolio management was very intresting and I decided to apply for the position.
Your use of empathetic voice tones give value to your answer and makes it sound more about how you feel as opposed to just reading through a script in a robotic fashion.