Characteristics clinical manifestation of schizophrenia are:
Formal thought diosrder
Delusions
Auditory hallucinations
Visual hallucinations
All the options are symptoms of schizophrenia. however, if the question asks about characteristic abnormality. the best answer is formal thought disorders. If a paicular formal thought disorder needs to be chosen, the best answer would be neologism
Schizophrenia Spectrum and Other Psychotic Disorders