Answer: C)32
The midsegment is half the length of the side parallel to it. In this case, BC is parallel to DE. So DE = (1/2)*BC = 0.5*64 = 32.
Note how AD = DB and AD+DB = AB. These facts can be used to prove that AD is half of AB. Similarly, we can prove AE is half of AC. To keep the same proportion, DE must be half of BC.