Final answer:
The best response is to tell the person you will find out the deadline for the permit application and follow up with them, rather than speculating or providing incorrect information.
Step-by-step explanation:
If a customer walks into the office and asks for the deadline to file a permit application and you do not know the answer, the best course of action would be to inform the person that you don't know but will find out. It's important to maintain professionalism and not speculate or provide potentially incorrect information. You can offer to refer the question to your supervisor or check the necessary resources to provide an accurate response. Moreover, reassuring the customer that you'll follow up with them as soon as you find the answer reflects good customer service ethics.