Invoking method from a different class

I have a method that I wish to invoke at a specific time from a different class. Is it possible to use the invoke function to call a method from a different class?

public class A {
    public void methodA()
    {
         //Do Something
    }
}

public class B {
     public void methodB()
     {
         //Do Something
         Invoke("MethodFromClassA", time);
     }
}

Is it possible? If so, how?

Something like this?

public class A
{
    public void FunctionA() { .. }
}

public class B
{
    private A referenceToInstanceA;

    public void FunctionB()
    {
        Invoke("CallFunctionA", time);
    }

    private void CallFunctionA()
    {
        referenceToInstanceOfA.FunctionA();
    }
}

Really dunno if this is the only way of doing it, but it probably works.
Hope you can accomplish that.