He 's crouched down , close to the ground , sniffing it cautiously . Then he lifts his nose to the air once more , turns his head either way , and inhales deeply . Then he lets out a small growl and turns to the other three while on all fours .
What may be a fact about this situation ?
A. A dog is getting aggressive .
B. A dog has discovered something .
C. None of the above choices .
D. A dog is ready to attack .


B