What will happen to the size of our sun as it gets older?

the old core of the Sun will cool and collapse into a dense but small hunk of mass known as a white dwarf star. ... As the Sun heats up and expands, life on Earth will become increasingly difficult. Long before the Sun becomes a red giant some 4 or 5 billion years from now, our planet will be rendered uninhabitable.

i think that c)gold was found there

but i am not sure

i need an image of the diagram