Should I normalize track?Should I reduce b/ground sound?

Whenever I want to burn a copy from an original cd, an option appears that asks if I want to 1)normalise tracks 2)reduce background sound.
Can somebody well versed in this please tell me if I should do the above? And if I did, will my buned copy be the exact as the original?
Also, if u advise to normalise. how many percent should I normalize?
What about instrumental cds? Di I normalise/reduce bgrd sound too?
Since I am new, pls educate me on these options