Answer:
Option B is correct.
The sides length of one side of the square is, 
Step-by-step explanation:
Area of square is given by:
unit square
where
A is the area of square
s is the length of one side of the square.
As per the statement:
The area of a square is
unit square.
To find the side length of one side of the square.
Using above formula: we have;
Substitute the given values;

or

Therefore, the sides length of one side of the square is, 