A diagram would be nice. The quick answer is C.
The first answer makes AE 8 which is twice as long as AC. I don't think the intent of the question is to use an external point.
The second one is also incorrect. This time E is in a place such that it makes AC and AE both equal and that too isn't possible.
The third one is the answer because D and E are both 1/2 the distance between the end point of the line containing them.
D is wrong because E is the midpoint of AC but D is not the midpoint of AB.
(6x^3/3x^4)^2 = (2/x)^2 = 4/x^2
