I do not think that there's a definitive answer. All three ways that have been mentioned thus far will create the results you are after.
Personally, I would either go with the page control as it eases design work considerably or, if there is large amounts of task specific code, with separate forms which I would derive from a common ancestor form to easily share looks and common functionality.
I am sure others would come up with yet unnamed methods to do things like this.....