Answer:
A. -6.5°C/km
Step-by-step explanation:
It's easier to find slope if we can locate two points.
Looking at the graph, it looks like it passes through the points (4, -10) and (7,-30).
To find the slope, we divide the difference of the y-coordinates by the difference of the x-coordinates. Here, the difference in the y-coordinates is:
-10 - (-30) = -10 + 30 = 20
The difference in the x-coordinates is:
4 - 7 = -3
So, the slope is:
20/(-3) = -20/3 ≈ -6.67
This is the closest to the first answer choice, -6.5°C/km, so that is the answer.