This is a question Apple makes you answer while submitting the app for review. It adds, in red print: Ensure that you select the correct answer for Advertising Identifier (IDFA) usage. If your app does contain the IDFA and you select No, the binary will be permanently rejected and you will have to submit a different binary.
Should we select yes or no? In case it is yes, what of these three options should we select?
1. Serve advertisements within the app
2. Attribute this app installation to a previously served advertisement
3. Attribute an action taken within this app to a previously served advertisement