This is a D. combustion reaction
That is because you add O2 which is necessary for a combustion, while the results are CO2 and water. What you are missing is a ---> after the 2O2 (g)
Sodium chloride is made from one sodium atom and one chlorine atom:
Sodium has a charge of +1, or just +.
Chlorine has a charge of -1, or just -.
These balance out.