What are two methods of writing a balanced formula?

Format Method - Writing the symbol of the cation and then the anion. Add whatever subscripts in order to balance the charges.

Crisscross Method - The numerical value of the charge of each ion is crossed over and becomes the subscripts for the other ion.

Only one reactant yields 2 or more products. meaning you will only have 1 product and it will break down into 2 or more products. eg. h2o -> h2 + o2

The answer is b because c don't explain why the moths are on them and it isn't a because as we know only one species of moth does this