Question

Light travels _______ until it strikes an object or moves from one medium to another

A.
in a zig-zag pattern
B.
perpendicular to its source
C.
in an unpredictable way
D.
in a straight line

Answer 1

All electromagnetic waves travel in a straight line (D) until they hit something that reflects or refracts or absorbs them, or until they hit the boundary at the beginning of a different medium.

That includes light, because light is an electromagnetic wave.

Answer 2

Light travels is a straight line so the answer is "D)."