You can read it of the graph which is (1,3) or also calculate it with vectors:
calculate the vector CD:
(5-(-3),2-4)=(8,-2)
to calculate the midpoint you need half of the vector length:
(8,-2)/2=(4,-1)
add the vector to C:
(-3,4)+(4,-1)=(1,3)=midpoint of CD
so it's the third option
