Answer:
The given statement is
In a triangle a segment joining the midpoints of two sides is one-half the length of the third side.
By, considering a Δ ABC and having mid points M and N
Angle A is common.

Δ A MN is similar to ΔABC.⇒[S AS]
As we know by CPCT if two triangles are similar their sides are proportional.
[M and N are mid points of AB and AC]
Out of all five options Option (E) △ABC with midpoints M and N is correct which satisfies the above statement.