Ifaequals the sum of the even integers from 2 to 100, inclusive, andbequals the sum of the odd integers from 1 to 99, inclusive, what is the value of a - b ?	Choose the most appropriate option
A) 1
B) 50
C) 19
D) 20
E) 21

Rationale: "this is a solution from beatthegmat : even numbers : ( 100 - 2 ) / 2 + 1 = 50 even integers . ( 100 + 2 ) / 2 = 51 is the average of the even set . sum = avg * ( # of elements ) = 51 * 50 = 2550 = a odd numbers : ( 99 - 1 ) / 2 + 1 = 50 odd integers . ( 99 + 1 ) / 2 = 50 is the average of the odd set . sum = avg * ( # of elements ) = 50 * 50 = 2500 = b a - b = 2550 - 2500 = 50 . ( b )"
Answer: B