Final answer:
In the second stage of Alzheimer's disease (AD), patients are unable to care for themselves and they begin to show signs of problems with mobility.
Step-by-step explanation:
The correct statement about patients in the second stage of AD is choice d. Both B and C are true. In the second stage of Alzheimer's disease (AD), patients are unable to care for themselves (option b) and they begin to show signs of problems with mobility (option c). This stage is considered moderate AD, characterized by increased memory, language, and cognitive deficits compared to mild AD.