Answer:
A. If there is nothing to interfere with light waves, they should travel in a straight line.
Explanation:
A light wave is a transverse wave, and do not require material medium for its propagation. It travels in straight lines in all directions from the source.
Light waves travel in straight paths (a principle referred to as the rectilinear propagation of light) known as rays, of which the combination of two or more rays gives a beam of light. When there is an obstruction on or interference with the path of light, it stops traveling in a straight line due to either absorption, refraction or diffraction.
When light from a source is forced to travel in one direction only, it is said to be polarized.
