A、11:00 a.m. B、1:00 p.m. C、3:00 p.m. D、5:00 a.m. D 文中提到在美国，最好不要在上午比较早的时间以及晚上11点之后打电话，因此答案是D。

In the United States, it is not customary to telephone someone very early in the morning. If you telephone him early in the day, while he is shaving or having breakfast, the time of the call shows the matter is very important and requires immediate attention. The same meaning is attached to phone calls made after 11: 00 p.m. If someone receives a call during sleeping hours, he assumes it is a matter of life or death. The time chosen for the call communicates its importance.
    If a late phone call is regarded in the U.S. as a cause for concern, imagine the excitement and fear caused by a crowd of people arriving at the door at 2: 00 a.m. On an island in the south Pacific, a plant manager from the U.S. had just such an experience. The natives of the island met one night to discuss a problem. When they arrived at a solution, they went to see the plant manager and woke him up to tell him what had been decided. Unfortunately, they did not know that it is a very serious matter to wake Americans at such an hour. The plant manager, who did not understand the local culture, thought there was a fight and called the police.