I think it’s A, because all of these are related to fossil fuel somehow.
2(NH4)3PO4 (aq) + 3Ni(NO3)2(aq) ------> Ni3(PO4)2(s) + 6NH4NO3 (aq)
Ni3(PO4)2 is a precipitate.
4Al+6Fe(NO3)2= 6Fe+4Al(NO3)3
The answer is B particles combine into a large amount of engery.
