Here, given the measures of the dimensions of the triangle CDE, we want to select which of the options must be true
Firstly, what we have to understand is that the higher the measure of the side of a triangle, the greater the angle facing it will be
From what we have, the angle facing EC will be the biggest, followed by DE and then lastly CD
Let us have a diagrammatic representation of the triangle to aid our selection;
As we can see from the diagrammatic representation above, angle D will be the largest, followed by angle C and then lastly angle E
So, we can now make our choice of correct option
As we can see, option A is the correct answer as it shows the proper arrangement of the magnitude of the angles