The available power required at a receiving antenna is 10-6 Watts. Transmitting and receiving antennas have gain of 40 dB each. The carrier frequency is 4 GHz and the distance between them is 30 miles. The required transmitter power is

• A. 0.64 W
• B. 0.71 W
• C. 0.78 W
• D. 0.32 W