Answer:
C
Explanation:
4(Al)+3(O2)==2(Al2O3)
Also, i'm in sixth grade just took a leson on a text book so may be wrong but i'm prety sure it's the correct nswer because x(Al)+y(O2) can not make hydregen for the h2o and for b, al+so2 = al2O3 makes sense but where did the sulfer go?
Answer: helium(He)
Explanation: Helium has only 2 electrons in the outermost energy level, but all of the other elements in its column have eight.