If a = 10 Cm, B = 3

If a = 1.0 cm, b = 3.0 cm, and I = 30 A, what is the magnitude of the magnetic field at point P?

A) 0.62 mT
B) 0.59 mT
C) 0.35 mT
D) 0.31 mT
E) 0.10 mT