I think you should always choose "none of the algorithms mentioned above". The question appears to be asking if the app implements its own custom encryption algorithms, and using encryption features built-in to iOS doesn't count. I think almost everything these days uses encryption features built-in to the system - including Construct's Cryptography plugin, and very likely including the Admob plugin - which doesn't apply to that question. There's very little reason for apps to implement their own custom encryption algorithms, but I guess for legal reasons Apple have to ask anyway just in case.