Light does not travel at a constant speed in a vacuum, compared to in air, because the light is being absorbed by atoms and molecules in the air. But light does travel at a constant speed in a vacuum.
So I agree with A
All that talk about moving forward is irrelevant (I think)
It should be organized in people
Where are the following answers?
The head of a matchstick has a great deal of chemical energy stored in it, including combustible substances that produce a flame when rubbed against a suitable surface. ... As the combustible materials burn, some of the chemical energy is transformed into heat energy, and some is transformed into light energy. Hope this helps