Which version of iOS should I choose for the virtual machine?

Question

iOS

Time for joy! I started building a simple webview app for iOS. I have a budget MacBook and the memory is only 128 GB. There was a choice:

Which version of iOS is better to download in order to achieve maximum compatibility? I can afford only 2-3 versions.
In pursuit: is it possible to somehow see iOS versions by region/district/geolocation of interest? This is to navigate the development, because. the target region is not covered everywhere with good internet and, presumably, about half of the users still go with older versions of iOS