I believe it’s D, please correct me if I’m wrong
I would say C, schizophrenia,
because schizophrenia is "a mental disorder that in many ways centers around not recognizing what is part of reality – namely, having psychotic breakdowns." It is not related to anxiety, as anxiety is classified as "neurotic" while schizophrenia is classified as "psychotic".
the emails we send allow the recipient to judge us solely based on our choice of tone, punctuation and writing ability. ... on the context of the message in which you incorporate an exclamation mark, readers can deduce your mood.