Among the following, the total number of compounds whose aqueous solutions turns red limus into blue litmus is  ${\text{KCN,\hspace{0.17em}K}}_{\text{2}}{\text{SO}}_{\text{4}}\text{,\hspace{0.17em}}{{\text{\hspace{0.17em}NaCl,\hspace{0.17em}Zn(NO}}_{\text{3}}\text{)}}_{\text{2}}{\text{,\hspace{0.17em}K}}_{\text{2}}{\text{CO}}_{\text{3}}{\text{,\hspace{0.17em}NH}}_{\text{4}}{\text{NO}}_{\text{3}}$