what is difference between Apple Authorized Resellers

All of them are the same: Apple Authorized Resellers. Shops that sell Apple products. You may find them with different names (for example, in Spain they are called "Apple Premium Resellers"), but they are the same.

Here's an idea. If you're looking for an "Apple Authorized Reseller", go to the bottom of this page and click on the line "find a reseller". The names you'll get are stores that have been authorized by Apple to sell Apple products. The only places I'd purchase an Apple product from are the Apple On-Line Store, an Apple Retail Store or an Apple Authorized Reseller.

It depends on the context in which you see those phrases. A store may be "authorized" to carry a number of products but not Apple products and hence not be an "Apple Authorized Reseller". Without knowing where you are seeing these phrases or what you are trying to find or learn, there's not much more we can say on the subject.

Regards.

Probably all the same, but if it doesn't say Apple authorised.... then the first question I would ask is "Authorised by Who?".