Find the value for m?
21(m + n) + 21 = 21(-m + n) + 21 Choose the correct option
A) 0  B) - 1  C) 1  D) 2  E) 3

Rationale: 21 m + 21 n - 21 = - 21 m + 21 n + 21 42 m = 42 = > m = 1 c
Answer: C