At What Distance from a Long Straight Wire Carrying a Current

Multiple Choice

At what distance from a long straight wire carrying a current of $5.0 \mathrm {~A}$ is the magnitude of the magnetic field due to the wire equal to the strength of Earth's magnetic field of about $5.0 \times 10 ^ { - 5 } \mathrm {~T}$ ? $\left( \mu _ { 0 } = 4 \pi \times 10 ^ { - 7 } \mathrm {~T} \cdot \mathrm { m } / \mathrm { A } \right)$

A) $1.0 \mathrm {~cm}$
B) $1.0 \mathrm {~mm}$
C) $4.0 \mathrm {~cm}$
D) $3.0 \mathrm {~cm}$
E) $2.0 \mathrm {~cm}$