[单选题]
At double the distance from a long current-car 8/lxpwr, e7vj1nn,zlryinxds3mpvx 7s67 g wire, the strength of the magn36v dss7m 7pxxetic field produced by that wire decreases to
A. 1/8 of its original value.
B. 1/4 of its original value.
C. 1/2 of its original value.
D. none of the given answers
