How are chemical and physical changes alike?

They are both changing things. There is a change in the mixture/substance

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

You would be correct, boiling water does disinfect contamination.    the property of disinfecting means to kill  germs, bacteria and other pathogens or contamination  that might cause an infection or cause a person to become sickly. a couple methods of disinfecting are using soap, other cleaning supplies or by simply "boiling" the contaminate.  the reason why boiling water disinfects certain attributes is because some cells cannot survive the heat and pressure.