Which of the following best describes the anther’s tone in this passage

A．while pushing asteroids off course nuclear weapons would destroy the world
B．asteroids racing across the night sky are likely to hit Earth in the near future
C．the worry about asteroids can be left to future generations since it is unlikely to happen in our lifetime
D．workable solutions still have to be found to prevent a collision of asteroids with Earth

A．It sounds practical but it may not solve the problem.
B．It may create more problems than it might solve.
C．It is a waste of money because a collision of asteroids with Earth is very unlikely.
D．Further research should be done before it is proved applicable.