A:K2SO4 BaCl2 NaNO3 NaCl
B:HCl Na2CO3 BaCl2 Na2SO4
C:KOH Na2SO4 CuSO4 NaCl
D:KCl AgNO3 KNO3 NaCl
( ) A will be a frog. It's black. It can swim in the river.