What is Shakespeare comparing two things for in sonnet 73

Answer: C, it talks about how, " That on the ashes of which his youth doth lie" meaning that his youth has burnt out, and "In me thou see'st the glowing of such fire" If you think about it, the flame is Shakespeare, and the "ashes of his youth" mean his life. He knows about approaching death " The deathbed whereon it must expire", and he has excepted it.