<span>A central or a main idea is an idea around which your entire paper or essay or paragraph or whatever it is you're writing, revolves. You have a central idea that you're trying to convey and everything you write or say somehow relates to that idea and proves a point that you're trying to make.</span>
Answer:
A star can live for billions of years: Option A.
Explanation:
The given excerpt clearly indicates that a star can run out of hydrogen and energy only after millions or billions of years. Only then it collapses to a little ball with gravity. This means it would live till those millions or billions of years.
'Black hole' is a region in the space which has such strong gravitational force that it pulls every object that passes through it. Albert Einstein predicted that black star would exist if a dead star also had enough gravity. Hence, "option A" is the correct one.
