In the following four items， which one is not the operational be

In the following four items， which one is not the operational benefits of GBAS（ ）.

A.A、one GBAS Ground Station will be able to support multiple runway ends

B.B、flight Inspection and maintenance requirements should be reduced

C.C、more stable signal， and less interference with preceding aircraft

D.D、need for “ critical areas ” required for ILS beam protection

正确答案是D