Answer:
b.) to a lower energy level
Step-by-step explanation:
A line spectrum is produced when an electron moves from one energy level to a lower energy level
The line spectrum arises from the de-excitation of a electron when it jumps back down to a lower energy orbit , emitting a photon of specific frequency. This photon, however, could be emitted in any direction, not just in the same direction as the original incident photon.