The exact year of Christ's birth is not recorded, but the calendar began on the supposed date divides time into B.C. (before Christ) and A.D. (in the year of our Lord). Nor was the exact day of his birth known. For the first 300 years his birthday was celebrated on different days. It was not until the year 354 that December25thwas chosen. Christmas music is loved by all who hear and sing it every year. Carols, bells, and merry music have been a part of Christmas for centuries. Every Christmas Eve the bells ring to call people to church services. The most famous sleigh bells in the world belong to Santa Claus. Christmas is a family festival. In the United States, no distance seems too great if it enables one to join the family circle for the holiday. All schools close for two weeks, parents welcome home their children and grandchildren and often open their doors to friends and strangers. The calendar began ______. A．in the exact year of Christ' birth B．on the exact date which divides time into B.C.and A.D. C．on December 25th D．on the chosen date