A.4 B.3 C.1 D.2
A.4.0m B.5.0m C.6.0m D.7.0m
A.4~5個立桿間距或5~7m B.6~8個立桿間距或7~9m C.8~10個立桿間距或8~10m D.2~4個立桿間距或2~4m