In these chemical equations, the letters A through D represent different elements. Which equation is balanced? A. AB + C2D → AD + 2CB
B. 2AB + 3C2D → 3CB + A2D3
C. 3A2B + C2D3 → 3AD + C2B3
D. 2AB3 + 3C2D → 6CB + A2D3

Harry lives in a city, and he has a lung condition known as asthma. on certain days, harry has to stay inside because pollutants in the air make it difficult for him to breathe. which of these pollution sources are nonpoint sources that might bother harry if he goes outside? choose the two that apply.