If (A-B-C+D = 18) and (A+B-C-D = 4), what is the value of (B-D)^2?	Choose the correct choice from the following options
A) 49 .  B) 8 .  C) 12 .  D) 16 .  E) 64 .

Rationale: "eq 1 : a - b - c + d = 18 eq 2 : a + b - c - d = 4 ( 1 ) subtract eq 1 from eq 2 a - b - c + d = 18 - a + b - c - d = 4 - - - - - - - - - - - - - - - - - - - - - - - - - 2 b + 2 d = 14 ( 2 ) simplify - b + d = 7 b - d = - 7 ( b - d ) ^ 2 = ( - 7 ) ^ 2 = 49 my answer : a"
Answer: A