What is the least value of k. So that 123k578 is divisible by 11.  Choose the correct answer
A) 8 B) 7 C) 5 D) 6 E) 4

Rationale: explanation : the difference of the sum of the digits at odd place and the sum of the digits at even place of the number , is either 0 or a number divisible by 11 . ( 1 + 3 + 5 + 8 ) - ( 2 + k + 7 ) = 17 - 9 - k = 8 - k therefore if k = 8 , then the value become zero . k = 8 is the least value so that 123 k 578 is divisible by 11 . answer : option a
Answer: A