Mine Clearance: What's the best way?

[Panzer VI]

In my current Smolensk '41 game as the Germans, I was able to easily send a single unit of Pioneers in to clear 1 hex of mines by themselves with minimal casualties and no disruptions. And that is with a total 5 adjacent Soviet Units. In my experience #3 is unnecessary in most situations, and #2 is practically a waste of troops if you playing with an Army like the Germans in 1941 where all the units have B morale or better. I would say #1 is your best bet.