Which of the following lights of a tractor may adversely affect visibility, if they are turned on while driving in fog?

Due to their high power and high angle of illumination, main beams cause intense reflection and scattering of light from water droplets in fog. This leads to the creation of the so-called 'wall of light' effect directly in front of the vehicle, which dazzles the driver and consequently drastically worsens, rather than improves, visibility.