A14-foot boat operating under oars after dark must show what color light to prevent a collision?

A "White" colored light must be shown by a 14-foot boat that is operating under oars after it is dark, in order to prevent a collision.

Boats which are less than 23 feet cannot exceed a maximum speed of 7 knots. They need to exhibit an all-around white light when it is sailing in the dark.

The other practicable sidelights can also be used instead of the white lights, when they are sailing in international waters.

Wavelength divides in half and speed stays the same.