Answer:
I would have to say B, E, C and F
Step-by-step explanation:
Danger or B, has a strong R ending, showing that it is an R controlled word. Per-form or E, also ends in a hard are sound, which indicates that it also is an R controlled word. I would go with sharpen, or C, because as a root Sharp, it is R controlled, and firmly, or F, because it also as a root Firm is an R controlled word.
Hope this helps:)