3000(0.25)=750
C is correct. Hope this helps!
we know that
If two lines are perpendicular, then the product o their slopes is equal to minus one
so

Step 1
<u>Find the slope of the given line</u>
we have

-------> 
This line is parallel to the y-axis
so
the perpendicular will be parallel to the x-axis
Step 2
The equation of the line perpendicular to the given line is the y-coordinate of the given point
Point 
the equation is

therefore
<u>the answer is</u>

see the attached figure to better understand the problem
This is how I would go about solving this, hope it helps.