In don't believe is static is part of the method signature because even though static methods are called:
Classname.StaticMethodName(..);
While instance methods are called:
var o = new Classname();
o.MethodName(..);
It still defines methods and parameters that match for the signature. See this for more on the static vs instance methods and signature: Static and Instance methods with the same name?
Access level is not part of the signature because you can't have:
public void DoThis();
private void DoThis();
Both methods have the same signature because signature is based on method, generic parameter(s), and method parameter(s)/types.
The following are valid:
public void DoThis();
private void DoThis(int x);
OR:
public void DoThis();
private int DoThis<int>();