asp.net - How to implement timezone in a web application? -

I want to implement the timezone in my web application. I researched and saw that most web apps use a GMT dropdown, here it is a link to the dropdown

Then I saw this article that UTC suggests that when the time zone is implemented It's basically saying that do not use DateTime.Now , instead of DateTime.UtcNow

my questions are,

1. Is there a dropdown of time zone in UTC, as I showed for the first time Was that one on GMT?
2. Should I really use UTC or GMT?

.NET 3.5 provides class that lets you populate a dropdown with time zone To make it relatively simple. GMT came before UTC and UTC officially started on January 1, 1972. See for more information. For today's purposes, both are very synonymous, although they have different historical roots, which looks and works better for their purposes.