G A mass spectrum. The peak at mass 100 has a 8% relative abundance. THe peak with mass 85 has a 40% abundance. The peak at 71 has a 3% abundance. The peak at 57 has a 30% abundance. The peak at mass 43 has a 100% abundance. The peak at mass 29 has a 18% abundance. In this mass spectrum, which peak most likely represents the molecular ion