The correct answer is B) blue color and lack of breathing. This is the correct answer because the blue color (cyanosis) and lack of breathing are clear signs that the person is not getting enough oxygen, which is the primary reason for administering artificial respiration. Irregular breathing (A) may or may not require artificial respiration, and vomiting (C) and unconsciousness (D) are secondary symptoms that could indicate the need for artificial respiration, but are not the primary indicators. The key is recognizing the lack of effective breathing and the blue color, which signal an immediate need to provide assisted ventilation through artificial respiration techniques.