A、Beauty. B、Loyalty. C、Luck. D、Durability. A短文中提到，钻戒代表美丽，故答案为A。

The period of engagement is the time between the marriage proposal and the wedding ceremony. Two people agree to marry when they decide to spend their lives together. The man usually gives the woman a diamond engagement ring. That tradition is said to have started when an Austrian man gave a diamond ring to the woman he wanted to marry. The diamond represented beauty. He placed it on the third finger of her left hand. He chose that finger because it was thought that the blood vessel in that finger went directly to the heart. Today we know that this is not true, yet the tradition continues.
    Americans generally are engaged for a period of about one year if they are planning a wedding ceremony and a party. During this time, friends of the bride may hold a party at which women friends and family members give the bride gifts that she will need as a wife. These could include cooking equipment or new clothing. Friends of the man who is getting married may have a bachelor party for him. This usually takes place the night before the wedding. Only men are invited to the bachelor party.
    During the marriage ceremony, the bride and her would-be husband usually exchange gold rings that represent the idea that their union will continue forever. The wife often wears both the wedding ring and the engagement ring on the same finger. The husband wears his ring on the third finger of his left hand. Many people say the purpose of the engagement period is to permit enough time to plan the wedding. But the main purpose is to let enough time pass so the two people are sure that they want to marry each other. Either person may decide to break the engagement, if this happens, the woman usually returns the ring to the man. They also return any wedding gifts they have received.
23. What was the diamond ring said to represent?
24. Why did the Austrian man place the diamond ring on the third finger of the left hand of his would-be wife?
25. What is the chief advantage of having the engagement period?