Read the passage and the questions...

Câu hỏi: Read the passage and the questions or unfinished sentences. Mark the letter A, B, C or D on your answer sheet that you think fits best.

A. has definitely solved the problem of unemployment

B. has brought a lot of benefits but has also created some serious problems

C. has led to an improvement in working conditions

D. can be regarded as the greatest technical achievement of the age