Final answer:
The correct statement is that electrons release energy as they move from high to low energy levels, leading to the emission of photons and the creation of an emission spectrum.
Step-by-step explanation:
The correct statement about a line emission spectrum is: d. Electrons release energy as they move from high to low energy levels. When electrons fall from a higher energy level to a lower one within an atom, they emit energy in the form of photons.
This process results in the production of emission lines in a spectrum, which correspond to the specific energy difference between the two levels. On the contrary, absorption occurs when electrons absorb energy and jump from a lower to a higher energy level, leading to absorption lines.