D. ![25\pi\text{ units}^2](/tpl/images/0438/9550/50eec.png)
Step-by-step explanation:
We have been given that diameter of a circle is 20 units.
To find the area of our given circle we will use area of circle formula.
, where r represents radius of circle.
let us find the radius of our given circle by dividing diameter by 2 as diameter is 2 times radius.
![\text{Radius of circle}=\frac{10}{2}](/tpl/images/0438/9550/831a1.png)
![\text{Radius of circle}=5](/tpl/images/0438/9550/149e7.png)
Upon substituting r=5 in area of circle formula we will get,
![\text{The area of circle}=\pi*\text{(5 units)}^2](/tpl/images/0438/9550/1fb45.png)
![\text{The area of circle}=\pi*25*\text{ units}^2](/tpl/images/0438/9550/86d2c.png)
![\text{The area of circle}=25\pi\text{ units}^2](/tpl/images/0438/9550/d75a7.png)
Therefore,the exact area of our given circle is
square units and option D is the correct choice.