Which phrase describes earth's magnetic declination?

I just took the test and got 100%

1: B, unlike poles repel each other

2: D, all of the above

3: A, domain; no

4: D, the angle between true north and north indicated by a compass

5: D, forms circles the go around the wire

6: D, causes alignment of the domains in the iron

7: B, the magnetic field B

8: C, perpendicular to both the current and the magnetic field

9: A, it rotates 180 degrees

r=rho l/a where a is the area, l is the length and rho is resistivity so the greater the area the lesser the resistance thats why the earth pin is thicker bcos current follow the shortest path, so less resistive .