You are a forensic scientist working at a crime scene outside along a fairly busy road. It is late at night and it is beginning to rain. You must finish what you are working on before the rain ruins the evidence. Because it is dark, you are afraid you will be hit by a passing car and decide to set up flares to divert traffic around the area. The labels on the flares have been partially torn and you cannot read which ones will burn when wet, so you look at the ingredient label on each one for a clue. Which flare should you use? A. Flare 3 contains potassium (K).
B. Flare 4 contains sulfur (S).
C. Flare 2 contains zinc (Zn).
D. Flare 1 contains magnesium (Mg).