\(N\) and \(M\) are each \(3\)-digit integers. Each of the numbers \(1, 2, 3, 6, 7,\) and \(8\) is a digit of either

[Vincen]

\(N\) and \(M\) are each \(3\)-digit integers. Each of the numbers \(1, 2, 3, 6, 7,\) and \(8\) is a digit of either \(N\) or \(M.\) What is the smallest possible positive difference between \(N\) and \(M?\)

A. 29
B. 49
C. 58
D. 113
E. 131

Answer: A

Source: GMAT Prep