Problem 3-9 - Vector sum

Find the magnitude and direction of the sum of the vectors $A + B + C$ using the component technique. Assume two significant digits.
$A = 20\; km$ north, $B = 30\; km$ east, $C = 50\; km\; 55 ^\circ$ west of north.

We have 3 vectors referred to the directions $\text{N, S, E, W}$ and we must choose a set of coordinate axes. Of course any $x, y$ set will do but which of the selections below would provide the simplest solution?

(A) 

(B)

(C)

(D)