What Was the Major Result of the Cross-National Collaborative Panic

What was the major result of the Cross-National Collaborative Panic Study?

A) Panic disorder occurs in all countries studied.
B) Panic disorder does not exist in some of the countries included in the study.
C) Mental health professionals in some countries do not recognize the symptoms of panic disorder as serious problems.
D) Differences in language and conceptualization of symptoms made it impossible to study similarities in the diagnosis of panic.