What is the exact meaning of croos section and cross sectional area of a conductor?

The cross section is the little tiny circle you see when you cut a wire
and look at the flat, cut end.

The cross-sectional area of the wire is the area of that little circle. 
It's equal to

                           Area = (pi) x (1/4) x (Diameter of the wire)²

Ibelieve your answer is b.hope this : )

Iwould sure like to answer your question but i honestly just don’t know