43. Which among the following is true about Alzheimer’s disease?
a. symptoms include prominent visual hallucinations, intense dreams involving movement and vocalizing and fluctuating cognitive symptoms
b. it is caused by meningitis, HIV, head traumas, brain tumors or by nutritional deficits such as vitamin B-complex
c. it is the result of a cardiovascular attack
d. it usually begins in difficulty remembering recent events, learning new material and irritability