Which of the following best expresses the main idea

A．A growing number of Americans are doubtful about what high technology can do in solving the world's problems.
B．Many scientists are beginning to believe that the better understanding of human beings will play a more decisive role in solving the world's problems.
C．More and more young scientists are trying their best to find new ways to solve the world's problems.
D．Technological creativity will still play a very important part in solving the world's problems.