In this question we can read. Which of the graphs represents a relationship between the quantities x and y where y always decreases as x increases?
If we see alternative "a", a constant value, ie when x increases y remains the same value then this alternative is wrong.
in alternative "b", we have a decrease of y as x increases, but after a moment it again makes y constant, so the alternative is wrong.
In alternative "c" we see the decrease of y as x increases, but then the opposite occurs and y increases as x increases.
In alternative "d", y increases, then decreases, and then decreases, but as it increases in the beginning then this is also wrong.
In the alternative "e" we have a slow decay, a faster one, and a slow one again, and so every path is with y decreasing along the x axis, that is, this is the correct alternative.
