In THIS LISTING, there are letter/number combinations after the title.
I have Bolded the number/letter combos.
What do they mean? 
Well, 3pc means there are 3 discs in the set. Dol means Dolby-encoded. Sub means subtitled. **Ac3 ** is the format.
Regarding Ac3–will it play in a regular DvD player, North American?
It doesn’t have to be silenus, I’ll take an answer from anybody. 
IIRC, AC3 used to be the super-duper-sexy sound technology of…1999 or so. I think your system can handle it.
-Joe
Dolby Digital (AC3), the successor to Dolby Pro Logic, is a lossy digital audio format capable of carrying up to 6 discrete sound channels, i.e., Dolby 5.1. AC3 and MP2 are DVD’s native audio formats so all DVD players are capable of reading AC3.
Thank you, one & all.
I just ordered the item linked to.