According to the given information:
1. C2C (Customer-to-Customer) commerce involves selling antique items.
2. B2C (Business-to-Consumer) commerce typically includes after-sale service.
3. B2B (Business-to-Business) commerce often involves collaborations.
Matching these descriptions with the given options, we have:
1. C2C - c (Selling antique items)
2. B2C - a (After-sale service)
3. B2B - b (Collaborations)
Therefore, the correct option is (A) 1-c, 2-a, 3-b