A、They’ re too costly to send. B、They’ re too reliant on humans. C、It’ s too expensive to build robots. D、It’ s hard to operate

W: John, I don’t really see why humans had to send astronauts into space. Robotics is so much more advanced now, why can’t they simply send robots?
M: Well, robotics has come a long way and it’s more expensive to send a manned spaceship into orbit, but the biggest problem with robots is that they have to be programmed for every possible eventuality.
W: Yes, I suppose you’re right. Robots just can’t react to situations independently the way humans do—they still need us to tell them what to do.
M: That’s right.
Q: Why can’t robots be sent into space instead of humans, according to the speakers?