Answer:
The behavior Gabriel's mother would observe is:
C. Gabriel stands on one leg for several hours.
Explanation:
Even though schizophrenia and catatonia may exist as completely separate conditions, it is not uncommon for them to be closely connected. Catatonia relates to unusual body movement. The individual may, for instance, move very little or not at all. In other cases, he may move in an excessive or peculiar manner. Among those strange behaviors is posturing. When posturing, the individual holds a posture or position that defies gravity.
Among the options, letter C seems to be the only one that is connected to catatonic schizophrenia. It most likely refers to posturing. The other options, even though they may very well be related to schizophrenia, are not symptoms of catatonia.
