Which of the following is wrong about the Fresnel zone?

Which of the following is wrong about the Fresnel zone?
A . The Fresnel zone of the radio wave beam is an ellipsoidal area directly surrounding the visible line of sight
B . The antenna installation position must ensure that the nodes on the two links are visible, and try to ensure that there are no obstructions in the Fresnel area
C . The nodes of the two sections of the site link are visible, and the blocked part of the Fresnel area boundary will not affect the link transmission effect
D . The sites are 2 kilometers apart , and the resulting Fresnel area is about 6 meters in radius

Answer: C