The correct option is A NH4NO3
Ammonium nitrate consists of ammonium ion and nitrate ion i.e. (NH4)+ and (NO3)−, which have a charge of +1 and -1 respectively. The charge and the symbol is given in the table:
SymbolNH4NO3Charge+1-1
On cross-multiplication and balancing the charge, we get the formula as NH4NO3.