55. What is the main idea of the passage?
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(A)] Most old people live longer today after an illness than people did years ago.
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(B)] Many old people are put into nursing homes by their families, who do not visit them regularly.
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(C)] Most elderly people are taken care of by their families, who assume the responsibility for different reasons.
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(D)] Most elderly people are satisfied with the better ways of caregiving that social workers have come up with.