We certainly have a line when we have an equation (or a function) like:
In this case, a, represent the slope of the line. If the slope of the line is negative, -a, the line will present the next representation (see the green and blue lines):
As we can see, the line goes down from left to right. As the values for x increase (from left to the right) the values for y decrease (from left to the right).
Therefore, the correct option is D (the one that fits better) ---> The line goes down and to the right.
(As I can see, this is the option that fits better from the explanation I wrote above ---and from the given options.)
Note: the graph for a line with positive slope, a, is of the form:
(As the values for x increase, the y values also increase.) ---> The line goes up and to the right.