Letsencrypt/certbot with ReadyNAS OS 6... --- update needed...

I try to install a letsencrypt certificate following the guidance here:

https://community.netgear.com/t5/Using-your-ReadyNAS-in-Business/Letsencrypt-certbot-experiments-with-ReadyNAS-OS-6-5-0-on-RN202/td-p/1090748

 

Unfortunately there seems to be some changes in the letsencrypt policy, I get

The standalone specific supported challenges flag is deprecated. Please use the --preferred-challenges flag instead.
Saving debug log to /var/log/letsencrypt/letsencrypt.log

How would you like to authenticate with the ACME CA?
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1: Apache Web Server plugin (apache)
2: Spin up a temporary webserver (standalone)
3: Place files in webroot directory (webroot)
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Select the appropriate number [1-3] then [enter] (press 'c' to cancel):

The guidance suggested "3 Automatically use a temporary ...", but this is no longer available and this is right in the middle of the procedure...

 

Can anybody help me here please how to continue with the provided choice today, so that I can follow further the described procedure?... Thank you!