A.490nmile B.3490nmile C.4910nmile D.4490nmile
A.15° B.75° C.015° D.075°
A.M船比N船所縮短航程的百分比大 B.N船比M船所縮短航程的百分比大 C.M船與N船所縮短航程的百分比相同 D.M船與N船所縮短的航程數(shù)相同