The question before was "Are you self-hosting any components of an e-mail server?" and if you answered "No" you didn't get to choose the client. And a webmail client is not part of what I consider an email server component without context.

But the survey also has other questions that are not clear enough. Like "Do you deploy a network-attached storage device (NAS)?" - what do they mean by NAS? As soon as I have network shares on it, it can be considered as a NAS. Do they mean all in one solutions like Synology or Qnap? Then why not make that more clear?