what is A ?

what is A.....why not B C D E but A
why so many die for it when can't get it on exam
why the people only look for A
because of A,i almost every weekend i fight with my 'good' brother
he is good in my parent eye because he get good result
then he can scorld me!!!!!?
A so big meh!!!
why everyone also want A !!!!!!!!!!!!!!!!!!