Which of the following statements about the second Fresnel zone are TRUE? (Multiple Choice)

Which of the following statements about the second Fresnel zone are TRUE? (Multiple Choice)
A . If the RF signal and primary signal have the same frequency and different phases and the two signals intersect, the RF signal weakens or even offsets the primary signal. Because reflection is one of the factors causing interference to the primary signal, impact of the second Fresnel zone on signals must be considered during evaluation of point-to-point communication links.
B . If signals in the second Fresnel zone are reflected to the receive end due to the antenna height and terrain, the link quality may degrade.
C . Impact of the second Fresnel zone should be considered during network planning and troubleshooting, especially in flat and dry environments (such as deserts).
D . The second Fresnel zone is surrounded by the first Fresnel zone.

Answer: ABC