Answer:
Option C : Circle is the correct answer.
Explanation:
Given that: 
Area formula;
A = πr²
Area is defined as the space occupied by a flat shape.
In this formula, 
π represents pi which is 3.14 
r represents radius.
Now, 
In the given options circle has a radius. Area of other shapes can also be find by side lengths.
Hence, 
Option C : Circle is the correct answer.