【正确答案】 B

【答案解析】[解析] Play is the principal business of childhood, and recent year research has shown the great importance of in the development of a person. From earliest stage of life, child needs opportunity and the right material for play, and the main tools are toys. They must be good ones, which children will play with often, and will come back to again and again. Therefore it is important to choose suitable toys for different stages of a child's development. In recent years research on infant development bas shown the standard a child is likely to reach is largely determined in the first three years of his life. So a baby's ability to profit from the right play materials is of great importance. A baby, who is encouraged and stimulated, talked to and shown things and played with, has the best chance of growing up successfully. The next stage, from three to five years old, curiosity knows no bounds. Every type of suitable toys should be made available to the child. Bricks and jigsaws and construction toys; painting, scribbling, and making things; sand and water play; toys for imaginative and pretending play; the first social games for learning to play and get on with others. By the third stage of play development — from five to seven or eight years — the child is at school. But for a few more years play is still the best way of learning, at home or at school. [解析] 本题属于主旨题，短文的主旨句一般出现在开头部分。由原文中的Play is the principal... in the development of a person可知答案为[B]。