Though the points are not labeled, I will do my best to explain the place where I am talking about, so that you can answer correctly.
The point where two organisms would have a common ancestor is the point where the lemur and loriee come from (red/yellow intersection, nearest to the early primate). This is because we can see that the yellow line split to become two different organisms. The early primate evolved into both the lemur and loriee, as shown by the split line. Unlike the other evolutions, where there is only one line. The common ancestor is an evolution that came before the lemur and loriee, however after the early primate, as indicated by the point of intersection between the yellow and red lines of the lemur and loriee.
Hope this helps!! :)