Step-by-step explanation
Let's assume that we have points of the form (x,y). If those points are reflected about the line x=a then the reflected points are given by:

So for example if we have the points D=(1,1) and E=(0,-2) and we reflect them about the line x=2 we get:

These points D' and E' are the same as those in the graph.
Answer
So the transformation performed in question 11 is a reflection about the line x=2 and it is described with this rule:
