Set A of 8 positive integers may have the same element and have 40. And set B of 8 positive integers must have different elements and have 40. When m and n are the greatest possible differences between 40 and other elements’ sums in set A and set B, respectively, m-n=?  Choose the correct choice from the following options:  A) 21  B) 29  C) 23  D) 25  E) 26

Rationale: this is maximum - minimum . hence , 40 - ( 1 + 1 + 1 + 1 + 1 + 1 + 1 ) = 32 and 40 - ( 1 + 2 + 3 + 4 + 5 + 6 + 7 ) = 11 . so , 32 - 11 = 21 . the correct answer is a .
Answer: A