What is the difference between public static, public and static methods in c#?

public: public by itself means this is an instance-based member that is accessible to external callers (those with access to the type itself).

static: static by itself means the member is not instance-based. You can call it without needing any particular instance (or even any instance at all). Without an accessibility qualifier, non-public is assumed – so the member will not be accessible to external callers

public static: public static is a static method that is accessible to external callers.