In Admiralty Sailing Directions, the distance unit used for sea is____than kilometer used at land

A、In Admiralty Sailing Directions, the distance unit used for sea is____than kilometer used at land
B、In Admiralty Sailing Directions, the distance unit used for sea is____than kilometer used at land
C、In Admiralty Sailing Directions, the distance unit used for sea is____than kilometer used at land
D、In Admiralty Sailing Directions, the distance unit used for sea is____than kilometer used at land
E、In Admiralty Sailing Directions, the distance unit used for sea is____than kilometer used at land
F、In Admiralty Sailing Directions, the distance unit used for sea is____than kilometer used at land
G:In Admiralty Sailing Directions, the distance unit used for sea is____than kilometer used at land
H:In Admiralty Sailing Directions, the distance unit used for sea is____than kilometer used at land