Question

Panel 1 is the answer choice

Panel 2 is the question

Answer 1

D is the midpoint of A and B
A = (0,s)
B = (r,0)

Add up the x coordinates to get 0+r = r. Then cut that in half to get r/2
Similarly, do the same for the y coordinates: s+0 = s ---> s/2

So the location of point D is (r/2, s/2)

Answer: Choice C