I think the answer would be A , break the darkness period with a flash of light for some time so that the plants can bloom all year round.
A vaccine can help keep people healthy and protect them from a certain virus. For example people in the United States get the flu shot when they get this shot the vaccine wont magically get rid of the virus but rather help them fight it off and protect them in the future if they keep up to date getting the vaccine
Hi! Number C. Aristotle
Hope this helps you! <3