There are many experts on this subject but ... if you are talking about oneworld Explorer (continent count-based), economy is M, business is D and first is A.

A and D are no problem in earning miles but M is the tricky part. I think if you could just list up the carriers you are going to fly with, then it may be easier to identify which 'M' miles would count toward AAdvantage.

Is (mileage-based) Global Explorer still on sale?