Which statement concerning Inmarsat-B and Inmarsat-C terminals is correct?

Correct Answer: Option B — Both Inmarsat-B and Inmarsat-C units are subject to shadowing effects, but Inmarsat-B units have directional antennas.

Shadowing occurs when an obstruction blocks the line-of-sight between the antenna and the satellite. While both systems are susceptible to this, Inmarsat-B is more sensitive due to its highly directional antenna, which requires a clear, unobstructed path to maintain the high-gain link necessary for voice and data services.