17. A radio station requires a coaxial cable to connect the transmitter to the antenna. The cable consists of an inner conductor with a diameter of 0.2 mm and an outer conductor with a diameter of 2.0 mm, whose thickness is negligible. If the maximum safe potential difference between the conductors is 2.3 kV, what is the maximum charge density the conductors can carry under this safety constraint? (A) 45 μC (B) 50 μC (C) 55 μC (D) 60μC (E) 65 μC