What is the main problem with reactive control methods?

A.Reaction takes time, so the robot will need to move slowly around the envrionment.

B. All of these choices ( except none )

C. None of these choices.

D. Can only execute pre-programmed routines, not adaptable, not really autonomous.

E. Requires more expensive sensors than other control methods.

F. Has a very high computational cost compared to other methods.