how to identify a multisite installation

Question

I am creating a plugin.

I want to add a different options page, based on multisite or single site.

I need a code which can identify installation is Multisite or single site.

Answer 1

The most obvious choice would be the is_multisite() conditional template tag.

Used as such:

if ( is_multisite() ) {
    // Multisite is enabled;
    // do something
}