Regex.Matches question

Please can someone tell me how is possible to put multiple 3rd argument in Regex.Matches function.
Declaration looks like this:
Regex.Matches(string, pattern, Regex.Options);
I need to include more than one Regexoptions.
I tried with:
Regex.Matches(string, pattern, RegexOptions.IgnoreCase && RegexOptions.Singleline && RegexOptions.Multiline);
and
Regex.Matches(string, pattern, RegexOptions.IgnoreCase + RegexOptions.Singleline + RegexOptions.Multiline);
but i get error here.
Is there any solution for that?
Thanks in advance