With Regard to the Treatment of Somatic Symptom Disorder and Illness

With regard to the treatment of somatic symptom disorder and illness anxiety disorder, research exploring the use of reassurance in a process called 'explanatory therapy' showed that

A) some significant gains were achieved.
B) reassurance did not work for hypochondriacs.
C) reassurance showed some gains but they lasted less than a few days.
D) the gains were so significant that participants were essentially 'cured'.