Andrew Ng machine learning course

Hi,

I was failing in the week 2 quiz - Machine learning course in Coursera.org, especially in one of the question which has multiple options (check boxes).

Which of the following are reasons for using feature scaling?

For the above question, I have attended the quiz many many times by selecting two items as answer (since it was check box option), i was keep failing the quiz.   

As a last choice, I submitted with one answer, I have completed the quiz.......  If you are also failing this question, try only one best answer you feel.   

Sorry, I forgot the answer :)

Thanks,