Which part of body swells in kwashiorkor?

Kwashiorkor is a severe form of malnutrition caused by a deficiency in dietary protein. One of the characteristic symptoms of kwashiorkor is the swelling or edema of the abdomen. This swelling is due to fluid retention and poor liver function, which is unable to produce adequate albumin to maintain fluid balance within the blood vessels.

Therefore, the correct answer is Abdomen.