The Chemical fomulla for Zinc Phosphate
Zn3(PO4)2
The answer is 2H2 + O2----> 2H2O
I would say B because c and d would decrease competition and a would do the same, or just kill the ecosystem.
Hope this helps and don't forget to hit that heart :)
There are 1000 meters in 1 Kilometer.
Hope this helps you. :)