单项选择题

TEXT B
Last summer, some twenty-eight thousand homeless people were offered shelter by the city of New York. Of this number, twelve thousand were children and six thousand were parents living together in families. The average child was six years old, the average parent twenty-seven. A typical homeless family included a mother with two or three children, but in about one-fifth of these families two parents were present. Roughly ten thousand single persons, then, made up the remainder of the population of the city’s shelter.
These proportions vary somewhat from one area of the nation to another. In all areas, however, families are the fastest-growing sector of the homeless population, and in the Northeast they are by far the largest sector already. In Massachusetts, three-fourths of the homeless now are families with children; in certain parts of Massachusetts--Attleboro and Northhampton, for example--the proportion reaches 90 percent. Two-thirds of the homeless children studied recently in Boston were less than five years old.
Of the estimated two to three million homeless people nationwide, about 500,000 are dependent children, according to Robert Hayes, counsel to the National Coalition for the Homeless. Including their parents, at least 750, 000 homeless people in America are family members.
What is to be made, then, of the supposition that the homeless are primarily the former residents of mental hospitals, persons who were carelessly released during the 1970s Many of them are, to be sure. Among the older men and women in the streets and shelters, as many as one-third (some believe as many as one-half) may be chronically disturbed, and a number of these people left mental hospitals during the 1970s. But in a city like New York, where nearly half the homeless are small children with an average of six, to operate on the basis of such a supposition makes no sense. Their parents, with an average age of twenty-seven, are not likely to have been hospitalized in the 1970s, either.
According to the passage, the author wants to tell us about ______.