using /etc/sudoers.d/ to change sudo time interval

I want to change my sudo time interval, so I looked up how. According to https://unix.stackexchange.com/quest...ssword-timeout, I'm supposed to add the following line to sudoers:Code:Defaults timestamp_timeout=[time]So I entered
Code:sudo visudoThen I noticed that the sudoers file says
Quote:

# Please consider adding local content in /etc/sudoers.d/ instead of # directly modifying this file.

Okay, so I went to /etc/sudoers.d. Which of those files do I need to add the line to? If I'm supposed to add the line to a new file, what should that be called?