听力原文： There are superstitions attached to numbers. Those numbers between 1 and 13 were in particular thought to have a powerful influence over the affairs of men. For example, it is commonly said that luck, good or bad, comes in three; if an accident happens, two more of the same kind may be expected soon afterwards. The arrival of a letter will be followed by two others within a certain period.
Another belief involving the number three has it that it is unlucky to light three cigarettes from one match. If this happens, the bad luck that goes with the deed falls upon the person whose cigarette was the last to be lit.
Seven was another significant number, usually regarded as a bringer of good luck. The ancient astrologers believed that the universe was governed by seven planets. Seven horseshoes nailed to a house will protect it from all evil.
Nine is usually thought of as a lucky number because it is the product of three times three. It was much used by the Anglo Saxons in their charms for healing.
Thirteen, as we well know, is regarded with great awe and fear. The common belief is that this derives from the fact that there were 13 people at Christ's last supper. In more modem times 13 is an especially unlucky number of a dinner party. For example, hotels will avoid numbering a floor the 13th and no room is given the number 13.
Yet oddly enough, to be born on the 13th of the month is not regarded with any fear at all, which just shows how irrational we are in our superstitious beliefs.
(30)

A. 3 and 7.
B. 7 and 9.
C. 3 and 9.
D. 3 and 13.