When a star reaches the black hole stage of its life

it is a very old star
it will give off new energy
it will grow in size
it is still a young star

A. It is a very old star

'cause when they reach their, it means they were very massive before, and for burning that amount of fuel, they took a very long time. So, we can say they are very old star.

Hope this helps!

Because the sun is the biggest and if the sun orbits the earth we will be dead probably