#### Answer

$x(2x+200)=40,000$

#### Work Step by Step

The length of the parking lot is given as $2x+200$ and the width is given as $ x$.
The total area is $40,000 yd^{2}$.
We know that the area of a rectangle is given by the product of length and breadth. ie,
$l\times b = $ Area of rectangle
Substituting the value of the length $(2x+200)$ and width $x$, we get
$x\times(2x+200)=40,000$
Or, $x(2x+200)=40,000$
Which is option A.