E9A05 - Amateur Extra Class

E9A05 : What does the term ground gain mean?
A The change in signal strength caused by grounding the antenna
B The gain of the antenna with respect to a dipole at ground level
C To force net gain to 0 dB by grounding part of the antenna
D An increase in signal strength from ground reflections in the environment of the antenna
Correct Answer: An increase in signal strength from ground reflections in the environment of the antenna