As a multiple-choice question, you can do it simply

ABCD is a parallelogram, and you can choose ABCD as a square (a square is a special parallelogram).

Let G be the midpoint of BC, and connect EG and AF at point O, as shown in the following figure:

|MO|=|EM|/2，|EM|=|AM|/2

= & gt|MO|=|AM|/4

= & gtAM = 4/5AO = 4/5(AE+EO)= 4/5AE+4/5 * 1/4AB = 4/5AE+ 1/5AB