The space between two concentric conducting spherical shells of radii b = 2.10 cm and a = 1.30 cm is filled with a substance of dielectric constant K = 18.4. A potential difference V = 93.0 V is applied across the shells. What is the electric field intensity in the substance?
A) 10.1 kV/m
B) 12.8 kV/m
C) 15.6 kV/m
D) 18.3 kV/m