As observed from the top of a lighthouse, 42 m high above sea-level, the angle of depression of a ship sailing directly towards it changes from 30° to 45°. The distance travelled by the ship during the period of observation is:
1
\(42(\sqrt 3 - 1)\)
2
\(42(\sqrt 3 + 1)\)
3
42
4
\(42(1 - \sqrt 3 )\)