Final answer:
Approximately 1.8 million females are affected by Alzheimer's disease, which is common in the elderly population, with a significant increase expected due to the aging baby-boomer generation.
Step-by-step explanation:
Of the 1.8 million individuals with Alzheimer's disease, the correct answer is b. female. Alzheimer's disease typically affects the elderly population, and evidence suggests that females are disproportionately affected compared to males. In the general discourse about Alzheimer's, it is well-known that the condition primarily affects older adults. According to statistics from 2012, approximately 5.4 million Americans suffered from Alzheimer's disease, with a prediction that the number could rise to as many as 13 million by the year 2050 due to the aging baby-boomer generation.