What does this notation denote?

What does this notation denote?

What does the following notation denote: $$\bigcup_{i=1}^\infty
\bigcap_{j\ge i}^\infty A_i$$
A. All elements that are in finitely many $A_i$;
B. All elements that are in infinitely many $A_i$;
C. All elements that are in all but infinite numbers of $A_i$;
Please help me, thank you.