Directions: There are five reading passages in this part. Each passage is followed by five questions. For each question there are four suggested answers marked A, B, C and D. Choose the best answer and blacken the corresponding letter on the answer sheet.Passage One Early in November 1965, New York was blacked out by an electricity failure (停电). The Mayor promised that it would not happen again. Pessimists (悲观主义者) were certain that it would happen again within five years. In July 1977, there was a repeat performance which produced a serious disorder throughout the city. At that time the city was in one of its worst heat waves. In 1965, there was little crime during the darkness, and fewer than a hundred people were arrested. In 1977, hundreds of stores were broken into and looted (劫掠). Nearly 4,000 people were arrested but far more disappeared into the darkness of the night. The number of policeman available was far from enough and some looters even carry guns. Hospitals had to treat hundreds of people cut by glass from shop windows. Banks and most business remained closed the next day. The blackout started at 9:30 P.M., when lightning hit and knocked out supply cables. Many stores were thus caught by surprise. For twenty-four hours, New York realized how helpless it was without electricity. What caused the blackout in July 1977（）

A. During a storm, lightning damaged cable.
Because of unemployment.
C. Heat waves had made people use too much electrical power.
D. Because the looters damaged the electricity supply.