Recall the types of chemical reactions and how they are typically written.
Synthesis : A + B ==> AB
Decomposition : AB ==> A + B
Double Replacement : AB + CD ==> AC + BD
Single Replacement : AB + C ==> AC + B
Now although it may seem that the given equation doesnt follow any of these as it has more parts, it follows decomposition. Decomposition is simply a single compound being broken up into two or more products. So it can be written as ABC ==> A + B + C as well therefore the answer is A
