Ampere's Law: a Type of Transmission Line for Electromagnetic Waves

Ampere's law: A type of transmission line for electromagnetic waves consists of two parallel conducting plates (assumed infinite in width) separated by a distance a. Each plate carries the same uniform surface current density of 16.0 A/m, but the currents run in opposite directions. What is the magnitude of the magnetic field between the plates at a point 1.00 mm from one of the plates if a = 0.800 cm? (μ₀ = 4π × 10^-7 T ∙ m/A)

A) 3.20 × 10^-3 T
B) 1.00 × 10^-5 T
C) 4.63 × 10^-5 T
D) 2.01 × 10^-5 T
E) 7.07 × 10^-4 T