Four Long Wires Are Perpendicular to the X-Y Plane

Multiple Choice

Four long wires are perpendicular to the x-y plane.Each wire carries the same magnitude current.Wire 1 goes through point (a,a,0) on the x-y plane,wire 2 goes through the point (-a,a,0) ,wire 3 goes through the point (-a,-a,0) ,and wire 4 goes through the point (a,-a,0) .Wires 1 and 3 carry their currents in the positive z direction and wires 2 and 4 carry their currents in the -z direction.What is the direction of the resulting magnetic field at the origin?

A) in the +x direction
B) in the -y direction
C) in the -x direction
D) There is no direction since the field is zero at this point.