The correct answer is D) Korsakoff's Syndrome.
Beltram's memory loss is probably due to Korsakoff's Syndrome.
The question clearly says that Beltram is currently 61 and has been a heavy drinker his entire life. Lately, he has started to have serious memory problems. So we cannot consider it Alzheimer's Disease.
Due to the heavy drinking problem, what Beltram has is Korsakoff's Syndrome. It is a memory disorder due to the deficiency in the body of vitamin B-1, or thiamine. And precisely heavy drinking can be a cause of the syndrome because of the toxic effect of alcohol in the cells of the brain.