Subscription Offer Codes in iOS 14

I'm looking to setup offer codes for my in-app purchases.

The support documentation here states the following:

Each offer code can be redeemed only once per customer, per offer. 

So does this mean:

(a) multiple customers can redeem the same code, albeit only once each; or
(b) each code can only be redeemed by one customer?

Also is there a way to track analytics for each code? (i.e. number of times redeemed, number of times these converted to paid, etc.)