Consider Two Current-Carrying Circular Loops

Multiple Choice

Consider two current-carrying circular loops. Both are made from one strand of wire and both carry the same current, but one has twice the radius of the other. Compared to the magnetic field at the center of the smaller loop, the magnetic field at the center of the larger loop is

A) 2 times stronger.
B) 8 times stronger.
C) neither 2, 4, or 8 times stronger.
D) 4 times stronger.