The paragraph is followed by an incomplete phrase or sentence which summarizes the main idea of the paragraph. Choose the missing words of the phrase or sentence.

At this juncture, as many as 57 per cent of children in America do not have full-time parental supervision either living with a single parent who works full time or in a two-parent household with both parents working full time. The lack of parental supervision for young children is nearly as great. As many as 49 per cent of children under age six do not have the benefit of full-time parenting, While some children enjoy suitable substitute supervision provided by friends and relatives or in day-care, far too many do not. 

The need of （） supervision.