A vessel constrained by her draught may，in addition to the lights prescribed for power-driven vessels in Rule 23，exhibit where they can best be seen（）or a cylinder.

单项选择题A vessel conducting mine clearing operations will show（）.

A.three balls in a vertical line
B.two balls in a vertical line
C.one ball near the foremast and one ball at each fore yard
D.one diamond near the foremast head and one ball at each fore yard

单项选择题A vessel being towed will show（）.

A.a forward masthead light
B.sidelights and a sternlight
C.a towing light
D.All of the above

单项选择题A vessel being towed astern shall show at night（）.

A.the lights required for a power-driven vessel underway
B.only the required masthead lights
C.a sternlight only
D.sidelights and a sternlight

单项选择题A vessel being pushed ahead is required to carry which of the following lights?（）.

A.Sidelights and a stern light
B.Sidelights only
C.Sidelights and a small white light at each end
D.A small white light at each end

单项选择题A vessel approaching your vessel from 235°relative is in what type of situation?（）.

A.Meeting
B.Overtaking
C.Crossing
D.Passing