Mass Psychogenic Illness Seems to Occur When

Mass psychogenic illness seems to occur when:

A) group leaders fail to provide non-ambiguous information
B) there is a perception of terrible danger
C) individuals mutually reinforce each other's concern about the occurrence of an unpleasant event
D) there is an unease which cannot be attributed to any specific cause
E) generalized anxiety builds up and a precipitating event occurs that allows it to be attached to an external threat