The average length of time between an individual's first symptoms of dissociative identity disorder and the identification and diagnosis of the disorder by a professional is

The average length of time between an individual's first symptoms of DID and the diagnosis is around 7 years. This is because it is commonly misdiagnosed (Usually as Bipolar Disorder) and because not many people are educated on the disorder so they may not seek treatment for it.

The correct answer is  b)