The correct answer is: John who has no genetic predisposition and goes dancing with his friends twice per week.
Alzheimer's disease is a neurodegenerative disease and the most common type of dementia. Patients suffering from this type of dementia exhibit problems with memory, cognition and behaviour. One of Alzheimer's risk factors is family history and genetic predisposition. Several genes have been found to increase the risk of developing Alzheimer's. Physical activity, such as regular dancing for example, stimulates the mind and can protect from dementia. Therefore, John is the least likely to develop Alzheimer's disease.