The figure above represents two charged, concentric conducting shells with radii R_1 and R_2. The space between the shells is filled with air. The dashed lines represent equipotentials. The electric field just outside the inner shell has magnitude E_1, and the electric field just inside the outer shell has magnitude E_2. Which of the following statements is true of the magnitude E of the electric field at point P? (a) E = 0 (b) E_1 > E > E_2 (c) E = E_1