The total amount of mechanical energy is conserved in free-fall situations (no external forces doing work). Thus, the potential energy that is lost is transformed into kinetic energy. The object loses 200 J of potential energy (PE loss = m * g * h where the m•g is 200 N (i.e., the object's weight).

Observe that a confusion of mass (~20 kg) and weight (200 N) will inevitably lead to the wrong answer.