It is either in the ones place or the hundred millions place
The answer would be the first choice. 
Explanation: The reason for this is that the question was pretty much just asking what the area of the resulting two-dimensional cross section would be -the shape in gray- (which can be found by using the formula
. To add on, since the dimensions of the shape are already given (5 and 3) all you've to do is multiply: 3*5=15
That's how you get to the answer.
<h3>
Answer: C) Discriminant</h3>
The formula for the discriminant is
d = b^2 - 4ac
If d < 0, then there are no real number solutions
If d = 0, then you have exactly one real solution
If d > 0, then you have two different real number solutions