It is c I hope I helped out with this question!.
Answer:
they had killed other animals
1:MgCO3 (s) + 2 NaNO3
2:agcl(s)+kno3(aq)
3:alcl3(aq)+h2(g)
4:NaNO3 + CO2 + H2O
(not sure abt last one)
