A cladogram is an image or a diagram that shows us an evolutionary relationship between different organisms. Up at the top we find the different organisms and their names. Along the side is where we find their characteristics. Anything that is past each characteristic will have that characteristic as you move up the cladogram. This diagram also shows which organisms are most closely related to one another.
Please see the image for an example. In this example we can see that the Koalas evolved after the trout.
The correct interpretation of the Cladogram would be : D. Koala evolved after trout (assuming that the cladogram is the same as the one that previously showed in this platform)