Which of the following is/are not true about Parkinson's disease?
• [A.] Parkinson's disease is caused by the degeneration of the substantia nigra in the midbrain.
• [B.] Parkinson's disease is caused by the degenerative loss of nigrostriatal dopaminergic neurons.
• [C.] Bradykinesia, rigidity and tremor are the main symptoms in Parkinson's disease.
• [D.] Parkinson's disease is caused by the degenerative loss of nigrostriatal cholinergic neurons.
Choose the correct answer from the options given below: