One afternoon on April, 1912, a new ship set off from England to America on it first trip. It was one of the largest and best ship at that time. It was cold, but the ship was pleasant and people are enjoying themselves. The next day was even cold. People who could see icebergs here or there. It was night. Suddenly, the man on watch shouting “Look out! Iceberg!” It was too late. A ship hit the iceberg and came to a stop. There was a very big hole in the ship and water began to come. Slowly the ship started to go down.

555定时器中含有（）个5K电阻。

A.0

B.1

C.2

D.3