Many School Systems Advocate Having Children Who Turn Five Just

Many school systems advocate having children who turn five just before the school entry deadline wait a year so that they will be more socially mature when they start kindergarten. What does the literature on IQ scores suggest about a possible consequence of this approach?

A) The delayed schooling may lower their IQs.
B) They may have higher IQs when they start school.
C) There may be effects on achievement but not on IQ.
D) Added social maturity may facilitate IQ development.