The correct choice is option A as follows;
[tex]\frac{AD}{AB}\text{ = }\frac{AB}{AC}[/tex]Here, we want to look at the correct ratio that should have been written
To write correct ratio, we need to identify similar triangles
Mathematically, when two triangles are similar, the ratio of their corresponding sides are equal
We take a look at the options given to check which is correct
Looking at the options, we have it that the correct choice here is considering the triangles ABD and triangle ABC as similar
Working with the individual bases, we have the correct ratio as;
[tex]\frac{AD}{AB}\text{ = }\frac{AB}{AC}[/tex]